diff --git a/ravenwood/Android.bp b/ravenwood/Android.bp
index c71b99f..be4cd76 100644
--- a/ravenwood/Android.bp
+++ b/ravenwood/Android.bp
@@ -211,6 +211,7 @@
     libs: [
         "junit",
         "flag-junit",
+        "framework-annotations-lib",
     ],
     visibility: ["//visibility:public"],
 }
diff --git a/ravenwood/bivalenttest/Android.bp b/ravenwood/bivalenttest/Android.bp
index 06cf08e6..e897735 100644
--- a/ravenwood/bivalenttest/Android.bp
+++ b/ravenwood/bivalenttest/Android.bp
@@ -39,6 +39,9 @@
         "androidx.test.ext.junit",
         "androidx.test.rules",
 
+        "junit-params",
+        "platform-parametric-runner-lib",
+
         // To make sure it won't cause VerifyError (b/324063814)
         "platformprotosnano",
     ],
@@ -65,6 +68,9 @@
         "androidx.test.ext.junit",
         "androidx.test.rules",
 
+        "junit-params",
+        "platform-parametric-runner-lib",
+
         "ravenwood-junit",
     ],
     jni_libs: [
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/CallTracker.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/CallTracker.java
new file mode 100644
index 0000000..8dadd39
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/CallTracker.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import static org.junit.Assert.fail;
+
+import static java.lang.StackWalker.Option.RETAIN_CLASS_REFERENCE;
+
+import android.util.Log;
+
+import java.lang.StackWalker.StackFrame;
+import java.util.HashMap;
+
+/**
+ * Used to keep track of and count the number of calls.
+ */
+public class CallTracker {
+    public static final String TAG = "CallTracker";
+
+    private final HashMap<String, Integer> mNumCalled = new HashMap<>();
+
+    /**
+     * Call it when a method is called. It increments the count for the calling method.
+     */
+    public void incrementMethodCallCount() {
+        var methodName = getCallingMethodName(1);
+
+        Log.i(TAG, "Method called: " + methodName);
+
+        mNumCalled.put(methodName, getNumCalled(methodName) + 1);
+    }
+
+    /**
+     * Return the number of calls of a method.
+     */
+    public int getNumCalled(String methodName) {
+        return mNumCalled.getOrDefault(methodName, 0);
+    }
+
+    /**
+     * Return the current method name. (with the class name.)
+     */
+    private static String getCallingMethodName(int frameOffset) {
+        var walker = StackWalker.getInstance(RETAIN_CLASS_REFERENCE);
+        var caller = walker.walk(frames ->
+                frames.skip(1 + frameOffset).findFirst().map(StackFrame::getMethodName)
+        );
+        return caller.get();
+    }
+
+    /**
+     * Check the number of calls stored in {@link #mNumCalled}.
+     */
+    protected void assertCalls(Object... methodNameAndCountPairs) {
+        // Create a local copy
+        HashMap<String, Integer> counts = new HashMap<>(mNumCalled);
+        for (int i = 0; i < methodNameAndCountPairs.length - 1; i += 2) {
+            String methodName = (String) methodNameAndCountPairs[i];
+            int expectedCount = (Integer) methodNameAndCountPairs[i + 1];
+
+            if (getNumCalled(methodName) != expectedCount) {
+                fail(String.format("Method %s: expected call count=%d, actual=%d",
+                        methodName, expectedCount, getNumCalled(methodName)));
+            }
+            counts.remove(methodName);
+        }
+        // All other entries are expected to be 0.
+        var sb = new StringBuilder();
+        for (var e : counts.entrySet()) {
+            if (e.getValue() == 0) {
+                continue;
+            }
+            sb.append(String.format("Method %s: expected call count=0, actual=%d",
+                    e.getKey(), e.getValue()));
+        }
+        if (sb.length() > 0) {
+            fail(sb.toString());
+        }
+    }
+
+    /**
+     * Same as {@link #assertCalls(Object...)} but it kills the process if it fails.
+     * Only use in @AfterClass.
+     */
+    protected void assertCallsOrDie(Object... methodNameAndCountPairs) {
+        try {
+            assertCalls(methodNameAndCountPairs);
+        } catch (Throwable th) {
+            // TODO: I don't think it's by spec, but the exception here would be ignored both on
+            // ravenwood and on the device side. Look into it.
+            Log.e(TAG, "*** Failure detected in @AfterClass! ***", th);
+            Log.e(TAG, "JUnit seems to ignore exceptions from @AfterClass, so killing self.");
+            System.exit(7);
+        }
+    }
+
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodAwareTestRunnerTest.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodAwareTestRunnerTest.java
new file mode 100644
index 0000000..d7c2c6c
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodAwareTestRunnerTest.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import static org.junit.Assert.assertFalse;
+
+import android.platform.test.annotations.DisabledOnRavenwood;
+import android.platform.test.ravenwood.RavenwoodAwareTestRunner.RavenwoodTestRunnerInitializing;
+import android.platform.test.ravenwood.RavenwoodRule;
+import android.util.Log;
+
+import junitparams.JUnitParamsRunner;
+import junitparams.Parameters;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Make sure RavenwoodAwareTestRunnerTest properly delegates to the original runner,
+ * and also run the special annotated methods.
+ */
+@RunWith(JUnitParamsRunner.class)
+public class RavenwoodAwareTestRunnerTest {
+    public static final String TAG = "RavenwoodAwareTestRunnerTest";
+
+    private static final CallTracker sCallTracker = new CallTracker();
+
+    private static int getExpectedRavenwoodRunnerInitializingNumCalls() {
+        return RavenwoodRule.isOnRavenwood() ? 1 : 0;
+    }
+
+    @RavenwoodTestRunnerInitializing
+    public static void ravenwoodRunnerInitializing() {
+        // No other calls should have been made.
+        sCallTracker.assertCalls();
+
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @BeforeClass
+    public static void beforeClass() {
+        sCallTracker.assertCalls(
+                "ravenwoodRunnerInitializing",
+                getExpectedRavenwoodRunnerInitializingNumCalls()
+        );
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Test
+    public void test1() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Test
+    @Parameters({"foo", "bar"})
+    public void testWithParams(String arg) {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Test
+    @DisabledOnRavenwood
+    public void testDeviceOnly() {
+        assertFalse(RavenwoodRule.isOnRavenwood());
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        Log.i(TAG, "afterClass called");
+
+        sCallTracker.assertCallsOrDie(
+                "ravenwoodRunnerInitializing",
+                getExpectedRavenwoodRunnerInitializingNumCalls(),
+                "beforeClass", 1,
+                "test1", 1,
+                "testWithParams", 2
+        );
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitClassRuleDeviceOnlyTest.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitClassRuleDeviceOnlyTest.java
new file mode 100644
index 0000000..0f8be0e
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitClassRuleDeviceOnlyTest.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import android.platform.test.annotations.DisabledOnRavenwood;
+import android.platform.test.ravenwood.RavenwoodRule;
+import android.util.Log;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@DisabledOnRavenwood
+public class RavenwoodImplicitClassRuleDeviceOnlyTest {
+    public static final String TAG = "RavenwoodImplicitClassRuleDeviceOnlyTest";
+
+    @BeforeClass
+    public static void beforeClass() {
+        Assert.assertFalse(RavenwoodRule.isOnRavenwood());
+    }
+
+    @Test
+    public void testDeviceOnly() {
+        Assert.assertFalse(RavenwoodRule.isOnRavenwood());
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        if (RavenwoodRule.isOnRavenwood()) {
+            Log.e(TAG, "Even @AfterClass shouldn't be executed!");
+            System.exit(1);
+        }
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleOrderRewriteTest.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleOrderRewriteTest.java
new file mode 100644
index 0000000..7ef40dc
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleOrderRewriteTest.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+import android.platform.test.ravenwood.RavenwoodRule;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Assume;
+import org.junit.ClassRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestRule;
+import org.junit.runner.RunWith;
+
+import java.util.HashMap;
+
+/**
+ * Make sure ravenizer will inject implicit rules and rewrite the existing rules' orders.
+ */
+@RunWith(AndroidJUnit4.class)
+public class RavenwoodImplicitRuleOrderRewriteTest {
+
+    private static final TestRule sEmptyRule = (statement, description) -> statement;
+
+    // We have two sets of 9 rules below, for class rules and instance rules.
+    // - Ravenizer will inject 2 more rules of each kind.
+    // - Ravenizer will adjust their order, so even though we'll add two sets of class and instance
+    //  rules with a MIN / MAX order, there will still be no duplicate in the order.
+
+    private static final int EXPECTED_RULE_COUNT = 9 + 2;
+
+    @ClassRule(order = Integer.MIN_VALUE)
+    public static final TestRule sRule01 = sEmptyRule;
+
+    @ClassRule(order = Integer.MIN_VALUE + 1)
+    public static final TestRule sRule02 = sEmptyRule;
+
+    @ClassRule(order = -10)
+    public static final TestRule sRule03 = sEmptyRule;
+
+    @ClassRule(order = -1)
+    public static final TestRule sRule04 = sEmptyRule;
+
+    @ClassRule(order = 0)
+    public static final TestRule sRule05 = sEmptyRule;
+
+    @ClassRule(order = 1)
+    public static final TestRule sRule06 = sEmptyRule;
+
+    @ClassRule(order = 10)
+    public static final TestRule sRule07 = sEmptyRule;
+
+    @ClassRule(order = Integer.MAX_VALUE - 1)
+    public static final TestRule sRule08 = sEmptyRule;
+
+    @ClassRule(order = Integer.MAX_VALUE)
+    public static final TestRule sRule09 = sEmptyRule;
+
+    @Rule(order = Integer.MIN_VALUE)
+    public final TestRule mRule01 = sEmptyRule;
+
+    @Rule(order = Integer.MIN_VALUE + 1)
+    public final TestRule mRule02 = sEmptyRule;
+
+    @Rule(order = -10)
+    public final TestRule mRule03 = sEmptyRule;
+
+    @Rule(order = -1)
+    public final TestRule mRule04 = sEmptyRule;
+
+    @Rule(order = 0)
+    public final TestRule mRule05 = sEmptyRule;
+
+    @Rule(order = 1)
+    public final TestRule mRule06 = sEmptyRule;
+
+    @Rule(order = 10)
+    public final TestRule mRule07 = sEmptyRule;
+
+    @Rule(order = Integer.MAX_VALUE - 1)
+    public final TestRule mRule08 = sEmptyRule;
+
+    @Rule(order = Integer.MAX_VALUE)
+    public final TestRule mRule09 = sEmptyRule;
+
+    private void checkRules(boolean classRule) {
+        final var anotClass = classRule ? ClassRule.class : Rule.class;
+
+        final HashMap<Integer, Integer> ordersUsed = new HashMap<>();
+
+        for (var field : this.getClass().getDeclaredFields()) {
+            if (!field.isAnnotationPresent(anotClass)) {
+                continue;
+            }
+            final var anot = field.getAnnotation(anotClass);
+            final int order = classRule ? ((ClassRule) anot).order() : ((Rule) anot).order();
+
+            if (ordersUsed.containsKey(order)) {
+                fail("Detected duplicate order=" + order);
+            }
+            ordersUsed.put(order, 1);
+        }
+        assertEquals(EXPECTED_RULE_COUNT, ordersUsed.size());
+    }
+
+    @Test
+    public void testClassRules() {
+        Assume.assumeTrue(RavenwoodRule.isOnRavenwood());
+
+        checkRules(true);
+    }
+
+    @Test
+    public void testInstanceRules() {
+        Assume.assumeTrue(RavenwoodRule.isOnRavenwood());
+
+        checkRules(false);
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleShadowingTest.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleShadowingTest.java
new file mode 100644
index 0000000..ae596b1
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleShadowingTest.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Test to make sure when a test class inherits another test class, the base class's
+ * implicit rules are shadowed and won't be executed.
+ *
+ * ... But for now, we don't have a way to programmatically check it, so for now we need to
+ * check the log file manually.
+ *
+ * TODO: Implement the test.
+ */
+@RunWith(AndroidJUnit4.class)
+public class RavenwoodImplicitRuleShadowingTest extends RavenwoodImplicitRuleShadowingTestBase {
+    @Test
+    public void testOkInSubClass() {
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleShadowingTestBase.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleShadowingTestBase.java
new file mode 100644
index 0000000..1ca97af
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodImplicitRuleShadowingTestBase.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * A test class that's just inherited by RavenwoodImplicitRuleShadowingTest.
+ */
+@RunWith(AndroidJUnit4.class)
+public abstract class RavenwoodImplicitRuleShadowingTestBase {
+    @Test
+    public void testOkInBaseClass() {
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithAndroidXRunnerTest.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithAndroidXRunnerTest.java
new file mode 100644
index 0000000..c042eb0
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithAndroidXRunnerTest.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import android.util.Log;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Make sure ravenwood's test runner works with {@link AndroidJUnit4}.
+ */
+@RunWith(AndroidJUnit4.class)
+public class RavenwoodRunnerWithAndroidXRunnerTest {
+    public static final String TAG = "RavenwoodRunnerWithAndroidXRunnerTest";
+
+    private static final CallTracker sCallTracker = new CallTracker();
+
+    @BeforeClass
+    public static void beforeClass() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Before
+    public void beforeTest() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @After
+    public void afterTest() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Test
+    public void test1() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Test
+    public void test2() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        Log.i(TAG, "afterClass called");
+
+        sCallTracker.assertCallsOrDie(
+                "beforeClass", 1,
+                "beforeTest", 2,
+                "afterTest", 2,
+                "test1", 1,
+                "test2", 1
+        );
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithJUnitParamsRunnerTest.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithJUnitParamsRunnerTest.java
new file mode 100644
index 0000000..2feb5ba
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithJUnitParamsRunnerTest.java
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import android.util.Log;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import junitparams.JUnitParamsRunner;
+import junitparams.Parameters;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Make sure ravenwood's test runner works with {@link AndroidJUnit4}.
+ */
+@RunWith(JUnitParamsRunner.class)
+public class RavenwoodRunnerWithJUnitParamsRunnerTest  {
+    public static final String TAG = "RavenwoodRunnerTest";
+
+    private static final CallTracker sCallTracker = new CallTracker();
+
+    @BeforeClass
+    public static void beforeClass() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Before
+    public void beforeTest() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @After
+    public void afterTest() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Test
+    public void testWithNoParams() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Test
+    @Parameters({"foo", "bar"})
+    public void testWithParams(String arg) {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        Log.i(TAG, "afterClass called");
+
+        sCallTracker.assertCallsOrDie(
+                "beforeClass", 1,
+                "beforeTest", 3,
+                "afterTest", 3,
+                "testWithNoParams", 1,
+                "testWithParams", 2
+        );
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithParameterizedAndroidJunit4Test.java b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithParameterizedAndroidJunit4Test.java
new file mode 100644
index 0000000..7e3bc0f
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/ravenwoodtest/bivalenttest/ravenizer/RavenwoodRunnerWithParameterizedAndroidJunit4Test.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.ravenwoodtest.bivalenttest.ravenizer;
+
+import android.util.Log;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import platform.test.runner.parameterized.ParameterizedAndroidJunit4;
+import platform.test.runner.parameterized.Parameters;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Make sure ravenwood's test runner works with {@link ParameterizedAndroidJunit4}.
+ */
+@RunWith(ParameterizedAndroidJunit4.class)
+public class RavenwoodRunnerWithParameterizedAndroidJunit4Test {
+    public static final String TAG = "RavenwoodRunnerTest";
+
+    private static final CallTracker sCallTracker = new CallTracker();
+
+    private final String mParam;
+
+    private static int sNumInsantiation = 0;
+
+    public RavenwoodRunnerWithParameterizedAndroidJunit4Test(String param) {
+        mParam = param;
+        sNumInsantiation++;
+    }
+
+    @BeforeClass
+    public static void beforeClass() {
+        // It seems like ParameterizedAndroidJunit4 calls the @BeforeTest / @AfterTest methods
+        // one time too many.
+        // With two parameters, this method should be called only twice, but it's actually
+        // called three times.
+        // So let's not check the number fo beforeClass calls.
+    }
+
+    @Before
+    public void beforeTest() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @After
+    public void afterTest() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @Parameters
+    public static List<String> getParams() {
+        var params =  new ArrayList<String>();
+        params.add("foo");
+        params.add("bar");
+        return params;
+    }
+
+    @Test
+    public void testWithParams() {
+        sCallTracker.incrementMethodCallCount();
+    }
+
+    @AfterClass
+    public static void afterClass() {
+        Log.i(TAG, "afterClass called");
+
+        sCallTracker.assertCallsOrDie(
+                "beforeTest", sNumInsantiation,
+                "afterTest", sNumInsantiation,
+                "testWithParams", sNumInsantiation
+        );
+    }
+}
diff --git a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodAwareTestRunnerHook.java b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodAwareTestRunnerHook.java
new file mode 100644
index 0000000..03600ad
--- /dev/null
+++ b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodAwareTestRunnerHook.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.platform.test.ravenwood;
+
+import static com.android.ravenwood.common.RavenwoodCommonUtils.RAVENWOOD_VERSION_JAVA_SYSPROP;
+
+import android.os.Bundle;
+import android.platform.test.ravenwood.RavenwoodAwareTestRunner.Order;
+import android.platform.test.ravenwood.RavenwoodAwareTestRunner.Scope;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import com.android.ravenwood.common.RavenwoodCommonUtils;
+
+import org.junit.runner.Description;
+import org.junit.runner.Runner;
+import org.junit.runners.model.TestClass;
+
+/**
+ * Provide hook points created by {@link RavenwoodAwareTestRunner}.
+ */
+public class RavenwoodAwareTestRunnerHook {
+    private static final String TAG = "RavenwoodAwareTestRunnerHook";
+
+    private RavenwoodAwareTestRunnerHook() {
+    }
+
+    private static void log(String message) {
+        RavenwoodCommonUtils.log(TAG, message);
+    }
+
+    public static void onRunnerInitializing(Runner runner, TestClass testClass) {
+        log("onRunnerStart: testClass=" + testClass + " runner=" + runner);
+
+        // TODO: Move the initialization code to a better place.
+
+        // This will let AndroidJUnit4 use the original runner.
+        System.setProperty("android.junit.runner",
+                "androidx.test.internal.runner.junit4.AndroidJUnit4ClassRunner");
+        System.setProperty(RAVENWOOD_VERSION_JAVA_SYSPROP, "1");
+
+        // This is needed to make AndroidJUnit4ClassRunner happy.
+        InstrumentationRegistry.registerInstance(null, Bundle.EMPTY);
+    }
+
+    public static boolean onBefore(RavenwoodAwareTestRunner runner, Description description,
+            Scope scope, Order order) {
+        log("onBefore: description=" + description + ", " + scope + ", " + order);
+
+        // Class-level annotations are checked by the runner already, so we only check
+        // method-level annotations here.
+        if (scope == Scope.Instance && order == Order.First) {
+            if (!RavenwoodRule.shouldEnableOnRavenwood(description)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static void onAfter(RavenwoodAwareTestRunner runner, Description description,
+            Scope scope, Order order, Throwable th) {
+        log("onAfter: description=" + description + ", " + scope + ", " + order + ", " + th);
+    }
+}
diff --git a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodAwareTestRunner.java b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodAwareTestRunner.java
new file mode 100644
index 0000000..a4fa41a
--- /dev/null
+++ b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodAwareTestRunner.java
@@ -0,0 +1,355 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.platform.test.ravenwood;
+
+import static android.platform.test.ravenwood.RavenwoodRule.shouldRunCassOnRavenwood;
+
+import static com.android.ravenwood.common.RavenwoodCommonUtils.ensureIsPublicVoidMethod;
+import static com.android.ravenwood.common.RavenwoodCommonUtils.isOnRavenwood;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+
+import com.android.ravenwood.common.RavenwoodCommonUtils;
+import com.android.ravenwood.common.SneakyThrow;
+
+import org.junit.Assume;
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runner.Runner;
+import org.junit.runner.manipulation.Filter;
+import org.junit.runner.manipulation.Filterable;
+import org.junit.runner.manipulation.InvalidOrderingException;
+import org.junit.runner.manipulation.NoTestsRemainException;
+import org.junit.runner.manipulation.Orderable;
+import org.junit.runner.manipulation.Orderer;
+import org.junit.runner.manipulation.Sortable;
+import org.junit.runner.manipulation.Sorter;
+import org.junit.runner.notification.RunNotifier;
+import org.junit.runners.BlockJUnit4ClassRunner;
+import org.junit.runners.model.Statement;
+import org.junit.runners.model.TestClass;
+
+import java.lang.annotation.Annotation;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.lang.reflect.InvocationTargetException;
+
+/**
+ * A test runner used for Ravenwood.
+ *
+ * TODO: Handle ENABLE_PROBE_IGNORED
+ *
+ * It will delegate to another runner specified with {@link InnerRunner}
+ * (default = {@link BlockJUnit4ClassRunner}) with the following features.
+ * - Add a {@link RavenwoodAwareTestRunnerHook#onRunnerInitializing} hook, which is called before
+ *   the inner runner gets a chance to run. This can be used to initialize stuff used by the
+ *   inner runner.
+ * - Add hook points, which are handed by RavenwoodAwareTestRunnerHook, with help from
+ *   the four test rules such as {@link #sImplicitClassMinRule}, which are also injected by
+ *   the ravenizer tool.
+ *
+ * We use this runner to:
+ * - Initialize the bare minimum environmnet just to be enough to make the actual test runners
+ *   happy.
+ * - Handle {@link android.platform.test.annotations.DisabledOnRavenwood}.
+ *
+ * This class is built such that it can also be used on a real device, but in that case
+ * it will basically just delegate to the inner wrapper, and won't do anything special.
+ * (no hooks, etc.)
+ */
+public class RavenwoodAwareTestRunner extends Runner implements Filterable, Orderable {
+    private static final String TAG = "RavenwoodAwareTestRunner";
+
+    @Inherited
+    @Target({TYPE})
+    @Retention(RetentionPolicy.RUNTIME)
+    public @interface InnerRunner {
+        Class<? extends Runner> value();
+    }
+
+    /**
+     * An annotation similar to JUnit's BeforeClass, but this gets executed before
+     * the inner runner is instantiated, and only on Ravenwood.
+     * It can be used to initialize what's needed by the inner runner.
+     */
+    @Target({METHOD})
+    @Retention(RetentionPolicy.RUNTIME)
+    public @interface RavenwoodTestRunnerInitializing {
+    }
+
+    /** Scope of a hook. */
+    public enum Scope {
+        Runner,
+        Class,
+        Instance,
+    }
+
+    /** Order of a hook. */
+    public enum Order {
+        First,
+        Last,
+    }
+
+    // The following four rule instances will be injected to tests by the Ravenizer tool.
+
+    public static final TestRule sImplicitClassMinRule = (base, description) ->
+            getCurrentRunner().updateStatement(base, description, Scope.Class, Order.First);
+
+    public static final TestRule sImplicitClassMaxRule = (base, description) ->
+            getCurrentRunner().updateStatement(base, description, Scope.Class, Order.Last);
+
+    public static final TestRule sImplicitInstMinRule = (base, description) ->
+            getCurrentRunner().updateStatement(base, description, Scope.Instance, Order.First);
+
+    public static final TestRule sImplicitInstMaxRule = (base, description) ->
+            getCurrentRunner().updateStatement(base, description, Scope.Instance, Order.Last);
+
+    public static final String IMPLICIT_CLASS_MIN_RULE_NAME = "sImplicitClassMinRule";
+    public static final String IMPLICIT_CLASS_MAX_RULE_NAME = "sImplicitClassMaxRule";
+    public static final String IMPLICIT_INST_MIN_RULE_NAME = "sImplicitInstMinRule";
+    public static final String IMPLICIT_INST_MAX_RULE_NAME = "sImplicitInstMaxRule";
+
+    /** Keeps track of the runner on the current thread. */
+    private static final ThreadLocal<RavenwoodAwareTestRunner> sCurrentRunner = new ThreadLocal<>();
+
+    private static RavenwoodAwareTestRunner getCurrentRunner() {
+        var runner = sCurrentRunner.get();
+        if (runner == null) {
+            throw new RuntimeException("Current test runner not set!");
+        }
+        return runner;
+    }
+
+    private final TestClass mTestClsas;
+    private final Runner mRealRunner;
+
+    /** Simple logging method. */
+    private void log(String message) {
+        RavenwoodCommonUtils.log(TAG, "[" + getTestClass() + "  @" + this + "] " + message);
+    }
+
+    private Error logAndFail(String message, Throwable innerException) {
+        log(message);
+        log("    Exception=" + innerException);
+        throw new AssertionError(message, innerException);
+    }
+
+    public TestClass getTestClass() {
+        return mTestClsas;
+    }
+
+    /**
+     * Constructor.
+     */
+    public RavenwoodAwareTestRunner(Class<?> testClass) {
+        mTestClsas = new TestClass(testClass);
+
+        /*
+         * If the class has @DisabledOnRavenwood, then we'll delegate to ClassSkippingTestRunner,
+         * which simply skips it.
+         */
+        if (isOnRavenwood() && !shouldRunCassOnRavenwood(mTestClsas.getJavaClass())) {
+            mRealRunner = new ClassSkippingTestRunner(mTestClsas);
+            return;
+        }
+
+        // Find the real runner.
+        final Class<? extends Runner> realRunner;
+        final InnerRunner innerRunnerAnnotation = mTestClsas.getAnnotation(InnerRunner.class);
+        if (innerRunnerAnnotation != null) {
+            realRunner = innerRunnerAnnotation.value();
+        } else {
+            // Default runner.
+            realRunner = BlockJUnit4ClassRunner.class;
+        }
+
+        onRunnerInitializing();
+
+        try {
+            log("Initializing the inner runner: " + realRunner);
+
+            mRealRunner = realRunner.getConstructor(Class.class).newInstance(testClass);
+
+        } catch (InstantiationException | IllegalAccessException
+                 | InvocationTargetException | NoSuchMethodException e) {
+            throw logAndFail("Failed to instantiate " + realRunner, e);
+        }
+    }
+
+    /**
+     * Run the bare minimum setup to initialize the wrapped runner.
+     */
+    // This method is called by the ctor, so never make it virtual.
+    private void onRunnerInitializing() {
+        if (!isOnRavenwood()) {
+            return;
+        }
+
+        log("onRunnerInitializing");
+
+        RavenwoodAwareTestRunnerHook.onRunnerInitializing(this, mTestClsas);
+
+        // Hook point to allow more customization.
+        runAnnotatedMethodsOnRavenwood(RavenwoodTestRunnerInitializing.class, null);
+    }
+
+    private void runAnnotatedMethodsOnRavenwood(Class<? extends Annotation> annotationClass,
+            Object instance) {
+        if (!isOnRavenwood()) {
+            return;
+        }
+        log("runAnnotatedMethodsOnRavenwood() " + annotationClass.getName());
+
+        for (var method : getTestClass().getAnnotatedMethods(annotationClass)) {
+            ensureIsPublicVoidMethod(method.getMethod(), /* isStatic=*/ instance == null);
+
+            var methodDesc = method.getDeclaringClass().getName() + "."
+                    + method.getMethod().toString();
+            try {
+                method.getMethod().invoke(instance);
+            } catch (IllegalAccessException | InvocationTargetException e) {
+                throw logAndFail("Caught exception while running method " + methodDesc, e);
+            }
+        }
+    }
+
+    @Override
+    public Description getDescription() {
+        return mRealRunner.getDescription();
+    }
+
+    @Override
+    public void run(RunNotifier notifier) {
+        if (mRealRunner instanceof ClassSkippingTestRunner) {
+            mRealRunner.run(notifier);
+            return;
+        }
+
+        sCurrentRunner.set(this);
+        try {
+            runWithHooks(getDescription(), Scope.Runner, Order.First,
+                    () -> mRealRunner.run(notifier));
+        } finally {
+            sCurrentRunner.remove();
+        }
+    }
+
+    @Override
+    public void filter(Filter filter) throws NoTestsRemainException {
+        if (mRealRunner instanceof Filterable r) {
+            r.filter(filter);
+        }
+    }
+
+    @Override
+    public void order(Orderer orderer) throws InvalidOrderingException {
+        if (mRealRunner instanceof Orderable r) {
+            r.order(orderer);
+        }
+    }
+
+    @Override
+    public void sort(Sorter sorter) {
+        if (mRealRunner instanceof Sortable r) {
+            r.sort(sorter);
+        }
+    }
+
+    private Statement updateStatement(Statement base, Description description, Scope scope,
+            Order order) {
+        if (!isOnRavenwood()) {
+            return base;
+        }
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                runWithHooks(description, scope, order, base);
+            }
+        };
+    }
+
+    private void runWithHooks(Description description, Scope scope, Order order, Runnable r) {
+        runWithHooks(description, scope, order, new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                r.run();
+            }
+        });
+    }
+
+    private void runWithHooks(Description description, Scope scope, Order order, Statement s) {
+        Throwable th = null;
+        if (isOnRavenwood()) {
+            Assume.assumeTrue(
+                    RavenwoodAwareTestRunnerHook.onBefore(this, description, scope, order));
+        }
+        try {
+            s.evaluate();
+        } catch (Throwable t) {
+            th = t;
+            SneakyThrow.sneakyThrow(t);
+        } finally {
+            if (isOnRavenwood()) {
+                RavenwoodAwareTestRunnerHook.onAfter(this, description, scope, order, th);
+            }
+        }
+    }
+
+    /**
+     * A runner that simply skips a class. It still has to support {@link Filterable}
+     * because otherwise the result still says "SKIPPED" even when it's not included in the
+     * filter.
+     */
+    private static class ClassSkippingTestRunner extends Runner implements Filterable {
+        private final TestClass mTestClass;
+        private final Description mDescription;
+        private boolean mFilteredOut;
+
+        ClassSkippingTestRunner(TestClass testClass) {
+            mTestClass = testClass;
+            mDescription = Description.createTestDescription(
+                    testClass.getJavaClass(), testClass.getJavaClass().getSimpleName());
+            mFilteredOut = false;
+        }
+
+        @Override
+        public Description getDescription() {
+            return mDescription;
+        }
+
+        @Override
+        public void run(RunNotifier notifier) {
+            if (mFilteredOut) {
+                return;
+            }
+            notifier.fireTestSuiteStarted(mDescription);
+            notifier.fireTestIgnored(mDescription);
+            notifier.fireTestSuiteFinished(mDescription);
+        }
+
+        @Override
+        public void filter(Filter filter) throws NoTestsRemainException {
+            if (filter.shouldRun(mDescription)) {
+                mFilteredOut = false;
+            } else {
+                throw new NoTestsRemainException();
+            }
+        }
+    }
+}
diff --git a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java
index 74de444..75faafb 100644
--- a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java
+++ b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java
@@ -60,10 +60,12 @@
 
     /**
      * When probing is enabled, all tests will be unconditionally run on Ravenwood to detect
-     * cases where a test is able to pass despite being marked as {@code IgnoreUnderRavenwood}.
+     * cases where a test is able to pass despite being marked as {@link DisabledOnRavenwood}.
      *
      * This is typically helpful for internal maintainers discovering tests that had previously
      * been ignored, but now have enough Ravenwood-supported functionality to be enabled.
+     *
+     * TODO: Rename it to a more descriptive name.
      */
     static final boolean ENABLE_PROBE_IGNORED = "1".equals(
             System.getenv("RAVENWOOD_RUN_DISABLED_TESTS"));
@@ -281,7 +283,7 @@
      * annotation, and an {@link EnabledOnRavenwood} annotation always takes precedence over
      * an {@link DisabledOnRavenwood} annotation.
      */
-    static boolean shouldEnableOnRavenwood(Description description) {
+    public static boolean shouldEnableOnRavenwood(Description description) {
         // First, consult any method-level annotations
         if (description.isTest()) {
             // Stopgap for http://g/ravenwood/EPAD-N5ntxM
@@ -300,20 +302,21 @@
         }
 
         // Otherwise, consult any class-level annotations
-        final var clazz = description.getTestClass();
+        return shouldRunCassOnRavenwood(description.getTestClass());
+    }
+
+    public static boolean shouldRunCassOnRavenwood(Class<?> clazz) {
         if (clazz != null) {
-            if (description.getTestClass().getAnnotation(EnabledOnRavenwood.class) != null) {
+            if (clazz.getAnnotation(EnabledOnRavenwood.class) != null) {
                 return true;
             }
-            if (description.getTestClass().getAnnotation(DisabledOnRavenwood.class) != null) {
+            if (clazz.getAnnotation(DisabledOnRavenwood.class) != null) {
                 return false;
             }
-            if (description.getTestClass().getAnnotation(IgnoreUnderRavenwood.class) != null) {
+            if (clazz.getAnnotation(IgnoreUnderRavenwood.class) != null) {
                 return false;
             }
         }
-
-        // When no annotations have been requested, assume test should be included
         return true;
     }
 
@@ -364,6 +367,7 @@
                 commonPrologue(base, description);
                 try {
                     base.evaluate();
+
                     RavenwoodRuleImpl.logTestRunner("finished", description);
                 } catch (Throwable t) {
                     RavenwoodRuleImpl.logTestRunner("failed", description);
diff --git a/ravenwood/junit-stub-src/android/platform/test/ravenwood/RavenwoodAwareTestRunnerHook.java b/ravenwood/junit-stub-src/android/platform/test/ravenwood/RavenwoodAwareTestRunnerHook.java
new file mode 100644
index 0000000..6b80e0c
--- /dev/null
+++ b/ravenwood/junit-stub-src/android/platform/test/ravenwood/RavenwoodAwareTestRunnerHook.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.platform.test.ravenwood;
+
+import android.platform.test.ravenwood.RavenwoodAwareTestRunner.Order;
+import android.platform.test.ravenwood.RavenwoodAwareTestRunner.Scope;
+
+import org.junit.runner.Description;
+import org.junit.runner.Runner;
+import org.junit.runners.model.TestClass;
+
+/**
+ * Provide hook points created by {@link RavenwoodAwareTestRunner}.
+ */
+public class RavenwoodAwareTestRunnerHook {
+    private RavenwoodAwareTestRunnerHook() {
+    }
+
+    /**
+     * Called when a runner starts, befre the inner runner gets a chance to run.
+     */
+    public static void onRunnerInitializing(Runner runner, TestClass testClass) {
+        // No-op on a real device.
+    }
+
+    public static boolean onBefore(RavenwoodAwareTestRunner runner, Description description,
+            Scope scope, Order order) {
+        // No-op on a real device.
+        return true;
+    }
+
+    public static void onAfter(RavenwoodAwareTestRunner runner, Description description,
+            Scope scope, Order order, Throwable th) {
+        // No-op on a real device.
+    }
+}
diff --git a/ravenwood/runtime-common-src/com/android/ravenwood/common/RavenwoodCommonUtils.java b/ravenwood/runtime-common-src/com/android/ravenwood/common/RavenwoodCommonUtils.java
index 9a11a8a..7b5bc5a 100644
--- a/ravenwood/runtime-common-src/com/android/ravenwood/common/RavenwoodCommonUtils.java
+++ b/ravenwood/runtime-common-src/com/android/ravenwood/common/RavenwoodCommonUtils.java
@@ -21,6 +21,8 @@
 import java.io.FileDescriptor;
 import java.io.FileInputStream;
 import java.io.PrintStream;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
 import java.util.Arrays;
 
 public class RavenwoodCommonUtils {
@@ -51,6 +53,8 @@
     public static final String RAVENWOOD_EMPTY_RESOURCES_APK =
             RAVENWOOD_RUNTIME_PATH + "ravenwood-data/ravenwood-empty-res.apk";
 
+    public static final String RAVENWOOD_VERSION_JAVA_SYSPROP = "android.ravenwood.version";
+
     // @GuardedBy("sLock")
     private static boolean sIntegrityChecked = false;
 
@@ -77,6 +81,18 @@
         return sEnableExtraRuntimeCheck;
     }
 
+    /** Simple logging method. */
+    public static void log(String tag, String message) {
+        // Avoid using Android's Log class, which could be broken for various reasons.
+        // (e.g. the JNI file doesn't exist for whatever reason)
+        System.out.print(tag + ": " + message + "\n");
+    }
+
+    /** Simple logging method. */
+    private void log(String tag, String format, Object... args) {
+        log(tag, String.format(format, args));
+    }
+
     /**
      * Load the main runtime JNI library.
      */
@@ -236,4 +252,17 @@
         var is = new FileInputStream(fd);
         RavenwoodCommonUtils.closeQuietly(is);
     }
+
+    public static void ensureIsPublicVoidMethod(Method method, boolean isStatic) {
+        var ok = Modifier.isPublic(method.getModifiers())
+                && (Modifier.isStatic(method.getModifiers()) == isStatic)
+                && (method.getReturnType() == void.class);
+        if (ok) {
+            return; // okay
+        }
+        throw new AssertionError(String.format(
+                "Method %s.%s() expected to be public %svoid",
+                method.getDeclaringClass().getName(), method.getName(),
+                (isStatic ? "static " : "")));
+    }
 }
diff --git a/ravenwood/runtime-helper-src/framework/com/android/platform/test/ravenwood/nativesubstitution/RavenwoodEnvironment_host.java b/ravenwood/runtime-helper-src/framework/com/android/platform/test/ravenwood/nativesubstitution/RavenwoodEnvironment_host.java
index 706a055..f894b0e 100644
--- a/ravenwood/runtime-helper-src/framework/com/android/platform/test/ravenwood/nativesubstitution/RavenwoodEnvironment_host.java
+++ b/ravenwood/runtime-helper-src/framework/com/android/platform/test/ravenwood/nativesubstitution/RavenwoodEnvironment_host.java
@@ -37,6 +37,9 @@
      * Called from {@link RavenwoodEnvironment#ensureRavenwoodInitialized()}.
      */
     public static void ensureRavenwoodInitialized() {
+
+        // TODO Unify it with the initialization code in RavenwoodAwareTestRunnerHook.
+
         synchronized (sInitializeLock) {
             if (sInitialized) {
                 return;
diff --git a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Exceptions.kt b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Exceptions.kt
new file mode 100644
index 0000000..3a7fab3
--- /dev/null
+++ b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Exceptions.kt
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@file:Suppress("ktlint:standard:filename")
+
+package com.android.platform.test.ravenwood.ravenizer
+
+/**
+ * Use it for internal exception that really shouldn't happen.
+ */
+class RavenizerInternalException(message: String) : Exception(message)
diff --git a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Ravenizer.kt b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Ravenizer.kt
index da9c7d9..e92ef72 100644
--- a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Ravenizer.kt
+++ b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Ravenizer.kt
@@ -20,7 +20,7 @@
 import com.android.hoststubgen.asm.zipEntryNameToClassName
 import com.android.hoststubgen.executableName
 import com.android.hoststubgen.log
-import com.android.platform.test.ravenwood.ravenizer.adapter.TestRunnerRewritingAdapter
+import com.android.platform.test.ravenwood.ravenizer.adapter.RunnerRewritingAdapter
 import org.objectweb.asm.ClassReader
 import org.objectweb.asm.ClassVisitor
 import org.objectweb.asm.ClassWriter
@@ -177,7 +177,8 @@
      * Whether a class needs to be processed. This must be kept in sync with [processSingleClass].
      */
     private fun shouldProcessClass(classes: ClassNodes, classInternalName: String): Boolean {
-        return TestRunnerRewritingAdapter.shouldProcess(classes, classInternalName)
+        return !classInternalName.shouldByBypassed()
+                && RunnerRewritingAdapter.shouldProcess(classes, classInternalName)
     }
 
     private fun processSingleClass(
@@ -191,6 +192,9 @@
 
         lateinit var data: ByteArray
         stats.totalConversionTime += log.vTime("Modify ${entry.name}") {
+
+            val classInternalName = zipEntryNameToClassName(entry.name)
+                ?: throw RavenizerInternalException("Unexpected zip entry name: ${entry.name}")
             val flags = ClassWriter.COMPUTE_MAXS
             val cw = ClassWriter(flags)
             var outVisitor: ClassVisitor = cw
@@ -201,7 +205,8 @@
             }
 
             // This must be kept in sync with shouldProcessClass.
-            outVisitor = TestRunnerRewritingAdapter(allClasses, outVisitor)
+            outVisitor = RunnerRewritingAdapter.maybeApply(
+                classInternalName, allClasses, outVisitor)
 
             cr.accept(outVisitor, ClassReader.EXPAND_FRAMES)
 
diff --git a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Utils.kt b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Utils.kt
index 0018648..e026e7a 100644
--- a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Utils.kt
+++ b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/Utils.kt
@@ -15,18 +15,31 @@
  */
 package com.android.platform.test.ravenwood.ravenizer
 
+import android.platform.test.ravenwood.RavenwoodAwareTestRunner
 import com.android.hoststubgen.asm.ClassNodes
 import com.android.hoststubgen.asm.findAnyAnnotation
+import com.android.hoststubgen.asm.startsWithAny
+import org.junit.rules.TestRule
+import org.junit.runner.RunWith
 import org.objectweb.asm.Type
 
-val junitTestMethodType = Type.getType(org.junit.Test::class.java)
-val junitRunWithType = Type.getType(org.junit.runner.RunWith::class.java)
+data class TypeHolder(
+    val clazz: Class<*>,
+) {
+    val type = Type.getType(clazz)
+    val desc = type.descriptor
+    val descAsSet = setOf<String>(desc)
+    val internlName = type.internalName
+}
 
-val junitTestMethodDescriptor = junitTestMethodType.descriptor
-val junitRunWithDescriptor = junitRunWithType.descriptor
+val testAnotType = TypeHolder(org.junit.Test::class.java)
+val ruleAnotType = TypeHolder(org.junit.Rule::class.java)
+val classRuleAnotType = TypeHolder(org.junit.ClassRule::class.java)
+val runWithAnotType = TypeHolder(RunWith::class.java)
+val innerRunnerAnotType = TypeHolder(RavenwoodAwareTestRunner.InnerRunner::class.java)
 
-val junitTestMethodDescriptors = setOf<String>(junitTestMethodDescriptor)
-val junitRunWithDescriptors = setOf<String>(junitRunWithDescriptor)
+val testRuleType = TypeHolder(TestRule::class.java)
+val ravenwoodTestRunnerType = TypeHolder(RavenwoodAwareTestRunner::class.java)
 
 /**
  * Returns true, if a test looks like it's a test class which needs to be processed.
@@ -39,16 +52,44 @@
 
     val cn = classes.findClass(className) ?: return false
 
-    if (cn.findAnyAnnotation(junitRunWithDescriptors) != null) {
+    if (cn.findAnyAnnotation(runWithAnotType.descAsSet) != null) {
         return true
     }
     cn.methods?.forEach { method ->
-        if (method.findAnyAnnotation(junitTestMethodDescriptors) != null) {
+        if (method.findAnyAnnotation(testAnotType.descAsSet) != null) {
             return true
         }
     }
+
+    // Check the super class.
     if (cn.superName == null) {
         return false
     }
     return isTestLookingClass(classes, cn.superName)
 }
+
+fun String.isRavenwoodClass(): Boolean {
+    return this.startsWithAny(
+        "com/android/hoststubgen/",
+        "android/platform/test/ravenwood",
+        "com/android/ravenwood/",
+        "com/android/platform/test/ravenwood/",
+    )
+}
+
+/**
+ * Classes that should never be modified.
+ */
+fun String.shouldByBypassed(): Boolean {
+    if (this.isRavenwoodClass()) {
+        return true
+    }
+    return this.startsWithAny(
+        "java/", // just in case...
+        "javax/",
+        "org/junit/",
+        "org/mockito/",
+        "kotlin/",
+        // TODO -- anything else?
+    )
+}
diff --git a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/adapter/RunnerRewritingAdapter.kt b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/adapter/RunnerRewritingAdapter.kt
new file mode 100644
index 0000000..25cad02
--- /dev/null
+++ b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/adapter/RunnerRewritingAdapter.kt
@@ -0,0 +1,453 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.platform.test.ravenwood.ravenizer.adapter
+
+import android.platform.test.ravenwood.RavenwoodAwareTestRunner
+import com.android.hoststubgen.ClassParseException
+import com.android.hoststubgen.asm.CLASS_INITIALIZER_DESC
+import com.android.hoststubgen.asm.CLASS_INITIALIZER_NAME
+import com.android.hoststubgen.asm.CTOR_NAME
+import com.android.hoststubgen.asm.ClassNodes
+import com.android.hoststubgen.asm.findAnnotationValueAsType
+import com.android.hoststubgen.asm.findAnyAnnotation
+import com.android.hoststubgen.asm.toHumanReadableClassName
+import com.android.hoststubgen.log
+import com.android.hoststubgen.visitors.OPCODE_VERSION
+import com.android.platform.test.ravenwood.ravenizer.RavenizerInternalException
+import com.android.platform.test.ravenwood.ravenizer.classRuleAnotType
+import com.android.platform.test.ravenwood.ravenizer.isTestLookingClass
+import com.android.platform.test.ravenwood.ravenizer.innerRunnerAnotType
+import com.android.platform.test.ravenwood.ravenizer.ravenwoodTestRunnerType
+import com.android.platform.test.ravenwood.ravenizer.ruleAnotType
+import com.android.platform.test.ravenwood.ravenizer.runWithAnotType
+import com.android.platform.test.ravenwood.ravenizer.testRuleType
+import org.objectweb.asm.AnnotationVisitor
+import org.objectweb.asm.ClassVisitor
+import org.objectweb.asm.FieldVisitor
+import org.objectweb.asm.MethodVisitor
+import org.objectweb.asm.Opcodes
+import org.objectweb.asm.Opcodes.ACC_FINAL
+import org.objectweb.asm.Opcodes.ACC_PUBLIC
+import org.objectweb.asm.Opcodes.ACC_STATIC
+import org.objectweb.asm.commons.AdviceAdapter
+import org.objectweb.asm.tree.ClassNode
+
+/**
+ * Class visitor to update the RunWith and inject some necessary rules.
+ *
+ * - Change the @RunWith(RavenwoodAwareTestRunner.class).
+ * - If the original class has a @RunWith(...), then change it to an @OrigRunWith(...).
+ * - Add RavenwoodAwareTestRunner's member rules as junit rules.
+ * - Update the order of the existing JUnit rules to make sure they don't use the MIN or MAX.
+ */
+class RunnerRewritingAdapter private constructor(
+    protected val classes: ClassNodes,
+    nextVisitor: ClassVisitor,
+) : ClassVisitor(OPCODE_VERSION, nextVisitor) {
+    /** Arbitrary cut-off point when deciding whether to change the order or an existing rule.*/
+    val RULE_ORDER_TWEAK_CUTOFF = 1973020500
+
+    /** Current class's internal name */
+    lateinit var classInternalName: String
+
+    /** [ClassNode] for the current class */
+    lateinit var classNode: ClassNode
+
+    /** True if this visitor is generating code. */
+    var isGeneratingCode = false
+
+    /** Run a [block] with [isGeneratingCode] set to true. */
+    private inline fun <T> generateCode(block: () -> T): T {
+        isGeneratingCode = true
+        try {
+            return block()
+        } finally {
+            isGeneratingCode = false
+        }
+    }
+
+    override fun visit(
+        version: Int,
+        access: Int,
+        name: String?,
+        signature: String?,
+        superName: String?,
+        interfaces: Array<out String>?,
+        ) {
+        classInternalName = name!!
+        classNode = classes.getClass(name)
+        if (!isTestLookingClass(classes, name)) {
+            throw RavenizerInternalException("This adapter shouldn't be used for non-test class")
+        }
+        super.visit(version, access, name, signature, superName, interfaces)
+
+        generateCode {
+            injectRunWithAnnotation()
+            if (!classes.hasClassInitializer(classInternalName)) {
+                injectStaticInitializer()
+            }
+            injectRules()
+        }
+    }
+
+    /**
+     * Remove the original @RunWith annotation.
+     */
+    override fun visitAnnotation(descriptor: String?, visible: Boolean): AnnotationVisitor? {
+        if (!isGeneratingCode && runWithAnotType.desc == descriptor) {
+            return null
+        }
+        return super.visitAnnotation(descriptor, visible)
+    }
+
+    override fun visitField(
+        access: Int,
+        name: String,
+        descriptor: String,
+        signature: String?,
+        value: Any?
+    ): FieldVisitor {
+        val fallback = super.visitField(access, name, descriptor, signature, value)
+        if (isGeneratingCode) {
+            return fallback
+        }
+        return FieldRuleOrderRewriter(name, fallback)
+    }
+
+    /** Inject an empty <clinit>. The body will be injected by [visitMethod]. */
+    private fun injectStaticInitializer() {
+        visitMethod(
+            Opcodes.ACC_PRIVATE or Opcodes.ACC_STATIC,
+            CLASS_INITIALIZER_NAME,
+            CLASS_INITIALIZER_DESC,
+            null,
+            null
+        )!!.let { mv ->
+            mv.visitCode()
+            mv.visitInsn(Opcodes.RETURN)
+            mv.visitMaxs(0, 0)
+            mv.visitEnd()
+        }
+    }
+
+    /**
+     * Inject `@RunWith(RavenwoodAwareTestRunner.class)`. If the class already has
+     * a `@RunWith`, then change it to add a `@OrigRunWith`.
+     */
+    private fun injectRunWithAnnotation() {
+        // Extract the original RunWith annotation and its value.
+        val runWith = classNode.findAnyAnnotation(runWithAnotType.descAsSet)
+        val runWithClass = runWith?.let { an ->
+            findAnnotationValueAsType(an, "value")
+        }
+
+        if (runWith != null) {
+            if (runWithClass == ravenwoodTestRunnerType.type) {
+                // It already uses RavenwoodTestRunner. We'll just keep it, but we need to
+                // inject it again because the original one is removed by visitAnnotation().
+                log.d("Class ${classInternalName.toHumanReadableClassName()}" +
+                        " already uses RavenwoodTestRunner.")
+                visitAnnotation(runWithAnotType.desc, true)!!.let { av ->
+                    av.visit("value", ravenwoodTestRunnerType)
+                    av.visitEnd()
+                }
+                return
+            }
+            if (runWithClass == null) {
+                throw ClassParseException("@RunWith annotation doesn't have a property \"value\""
+                        + " in class ${classInternalName.toHumanReadableClassName()}")
+            }
+
+            // Inject an @OrigRunWith.
+            visitAnnotation(innerRunnerAnotType.desc, true)!!.let { av ->
+                av.visit("value", runWithClass)
+                av.visitEnd()
+            }
+        }
+
+        // Inject a @RunWith(RavenwoodAwareTestRunner.class).
+        visitAnnotation(runWithAnotType.desc, true)!!.let { av ->
+            av.visit("value", ravenwoodTestRunnerType.type)
+            av.visitEnd()
+        }
+        log.d("Processed ${classInternalName.toHumanReadableClassName()}")
+    }
+
+    /*
+     Generate the fields and the ctor, which should looks like  this:
+
+  public static final org.junit.rules.TestRule sRavenwoodImplicitClassMinRule;
+    descriptor: Lorg/junit/rules/TestRule;
+    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
+    RuntimeVisibleAnnotations:
+      0: #49(#50=I#51)
+        org.junit.ClassRule(
+          order=-2147483648
+        )
+
+  public static final org.junit.rules.TestRule sRavenwoodImplicitClassMaxRule;
+    descriptor: Lorg/junit/rules/TestRule;
+    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
+    RuntimeVisibleAnnotations:
+      0: #49(#50=I#52)
+        org.junit.ClassRule(
+          order=2147483647
+        )
+
+  public final org.junit.rules.TestRule sRavenwoodImplicitInstanceMinRule;
+    descriptor: Lorg/junit/rules/TestRule;
+    flags: (0x0011) ACC_PUBLIC, ACC_FINAL
+    RuntimeVisibleAnnotations:
+      0: #53(#50=I#51)
+        org.junit.Rule(
+          order=-2147483648
+        )
+
+  public final org.junit.rules.TestRule sRavenwoodImplicitInstanceMaxRule;
+    descriptor: Lorg/junit/rules/TestRule;
+    flags: (0x0011) ACC_PUBLIC, ACC_FINAL
+    RuntimeVisibleAnnotations:
+      0: #53(#50=I#52)
+        org.junit.Rule(
+          order=2147483647
+        )
+     */
+
+    val sRavenwood_ClassRuleMin = "sRavenwood_ClassRuleMin"
+    val sRavenwood_ClassRuleMax = "sRavenwood_ClassRuleMax"
+    val mRavenwood_InstRuleMin = "mRavenwood_InstRuleMin"
+    val mRavenwood_InstRuleMax = "mRavenwood_InstRuleMax"
+
+    private fun injectRules() {
+        injectRule(sRavenwood_ClassRuleMin, true, Integer.MIN_VALUE)
+        injectRule(sRavenwood_ClassRuleMax, true, Integer.MAX_VALUE)
+        injectRule(mRavenwood_InstRuleMin, false, Integer.MIN_VALUE)
+        injectRule(mRavenwood_InstRuleMax, false, Integer.MAX_VALUE)
+    }
+
+    private fun injectRule(fieldName: String, isStatic: Boolean, order: Int) {
+        visitField(
+            ACC_PUBLIC or ACC_FINAL or (if (isStatic) ACC_STATIC else 0),
+            fieldName,
+            testRuleType.desc,
+            null,
+            null,
+        ).let { fv ->
+            val anot = if (isStatic) { classRuleAnotType } else { ruleAnotType }
+            fv.visitAnnotation(anot.desc, true).let {
+                it.visit("order", order)
+                it.visitEnd()
+            }
+            fv.visitEnd()
+        }
+    }
+
+    override fun visitMethod(
+        access: Int,
+        name: String,
+        descriptor: String,
+        signature: String?,
+        exceptions: Array<String>?,
+    ): MethodVisitor {
+        val next = super.visitMethod(access, name, descriptor, signature, exceptions)
+        if (name == CLASS_INITIALIZER_NAME && descriptor == CLASS_INITIALIZER_DESC) {
+            return ClassInitializerVisitor(
+                access, name, descriptor, signature, exceptions, next)
+        }
+        if (name == CTOR_NAME) {
+            return ConstructorVisitor(
+                access, name, descriptor, signature, exceptions, next)
+        }
+        return next
+    }
+
+    /*
+
+  static {};
+    descriptor: ()V
+    flags: (0x0008) ACC_STATIC
+    Code:
+      stack=1, locals=0, args_size=0
+         0: getstatic     #36                 // Field android/platform/test/ravenwood/RavenwoodAwareTestRunner.RavenwoodImplicitClassMinRule:Lorg/junit/rules/TestRule;
+         3: putstatic     #39                 // Field sRavenwoodImplicitClassMinRule:Lorg/junit/rules/TestRule;
+         6: getstatic     #42                 // Field android/platform/test/ravenwood/RavenwoodAwareTestRunner.RavenwoodImplicitClassMaxRule:Lorg/junit/rules/TestRule;
+         9: putstatic     #45                 // Field sRavenwoodImplicitClassMaxRule:Lorg/junit/rules/TestRule;
+        12: return
+      LineNumberTable:
+        line 33: 0
+        line 36: 6
+     */
+    private inner class ClassInitializerVisitor(
+        access: Int,
+        val name: String,
+        val descriptor: String,
+        signature: String?,
+        exceptions: Array<String>?,
+        next: MethodVisitor?,
+    ) : MethodVisitor(OPCODE_VERSION, next) {
+        override fun visitCode() {
+            visitFieldInsn(Opcodes.GETSTATIC,
+                ravenwoodTestRunnerType.internlName,
+                RavenwoodAwareTestRunner.IMPLICIT_CLASS_MIN_RULE_NAME,
+                testRuleType.desc
+            )
+            visitFieldInsn(Opcodes.PUTSTATIC,
+                classInternalName,
+                sRavenwood_ClassRuleMin,
+                testRuleType.desc
+            )
+
+            visitFieldInsn(Opcodes.GETSTATIC,
+                ravenwoodTestRunnerType.internlName,
+                RavenwoodAwareTestRunner.IMPLICIT_CLASS_MAX_RULE_NAME,
+                testRuleType.desc
+            )
+            visitFieldInsn(Opcodes.PUTSTATIC,
+                classInternalName,
+                sRavenwood_ClassRuleMax,
+                testRuleType.desc
+            )
+
+            super.visitCode()
+        }
+    }
+
+    /*
+  public com.android.ravenwoodtest.bivalenttest.runnertest.RavenwoodRunnerTest();
+    descriptor: ()V
+    flags: (0x0001) ACC_PUBLIC
+    Code:
+      stack=2, locals=1, args_size=1
+         0: aload_0
+         1: invokespecial #1                  // Method java/lang/Object."<init>":()V
+         4: aload_0
+         5: getstatic     #7                  // Field android/platform/test/ravenwood/RavenwoodAwareTestRunner.RavenwoodImplicitInstanceMinRule:Lorg/junit/rules/TestRule;
+         8: putfield      #13                 // Field sRavenwoodImplicitInstanceMinRule:Lorg/junit/rules/TestRule;
+        11: aload_0
+        12: getstatic     #18                 // Field android/platform/test/ravenwood/RavenwoodAwareTestRunner.RavenwoodImplicitInstanceMaxRule:Lorg/junit/rules/TestRule;
+        15: putfield      #21                 // Field sRavenwoodImplicitInstanceMaxRule:Lorg/junit/rules/TestRule;
+        18: return
+      LineNumberTable:
+        line 31: 0
+        line 38: 4
+        line 41: 11
+      LocalVariableTable:
+        Start  Length  Slot  Name   Signature
+            0      19     0  this   Lcom/android/ravenwoodtest/bivalenttest/runnertest/RavenwoodRunnerTest;
+     */
+    private inner class ConstructorVisitor(
+        access: Int,
+        name: String,
+        descriptor: String,
+        signature: String?,
+        exceptions: Array<String>?,
+        next: MethodVisitor?,
+    ) : AdviceAdapter(OPCODE_VERSION, next, ACC_ENUM, name, descriptor) {
+        override fun onMethodEnter() {
+            visitVarInsn(ALOAD, 0)
+            visitFieldInsn(Opcodes.GETSTATIC,
+                ravenwoodTestRunnerType.internlName,
+                RavenwoodAwareTestRunner.IMPLICIT_INST_MIN_RULE_NAME,
+                testRuleType.desc
+            )
+            visitFieldInsn(Opcodes.PUTFIELD,
+                classInternalName,
+                mRavenwood_InstRuleMin,
+                testRuleType.desc
+            )
+
+            visitVarInsn(ALOAD, 0)
+            visitFieldInsn(Opcodes.GETSTATIC,
+                ravenwoodTestRunnerType.internlName,
+                RavenwoodAwareTestRunner.IMPLICIT_INST_MAX_RULE_NAME,
+                testRuleType.desc
+            )
+            visitFieldInsn(Opcodes.PUTFIELD,
+                classInternalName,
+                mRavenwood_InstRuleMax,
+                testRuleType.desc
+            )
+        }
+    }
+
+    /**
+     * Rewrite "order" of the existing junit rules to make sure no rules use a MAX or MIN order.
+     *
+     * Currently, we do it a hacky way -- use an arbitrary cut-off point, and if the order
+     * is larger than that, decrement by 1, and if it's smaller than the negative cut-off point,
+     * increment it by 1.
+     *
+     * (or the arbitrary number is already used.... then we're unlucky, let's change the cut-off
+     * point.)
+     */
+    private inner class FieldRuleOrderRewriter(
+        val fieldName: String,
+        next: FieldVisitor,
+    ) : FieldVisitor(OPCODE_VERSION, next) {
+        override fun visitAnnotation(descriptor: String?, visible: Boolean): AnnotationVisitor {
+            val fallback = super.visitAnnotation(descriptor, visible)
+            if (descriptor != ruleAnotType.desc && descriptor != classRuleAnotType.desc) {
+                return fallback
+            }
+            return RuleOrderRewriter(fallback)
+        }
+
+        private inner class RuleOrderRewriter(
+            next: AnnotationVisitor,
+        ) : AnnotationVisitor(OPCODE_VERSION, next) {
+            override fun visit(name: String?, origValue: Any?) {
+                if (name != "order") {
+                    return super.visit(name, origValue)
+                }
+                var order = origValue as Int
+                if (order == RULE_ORDER_TWEAK_CUTOFF || order == -RULE_ORDER_TWEAK_CUTOFF) {
+                    // Oops. If this happens, we'll need to change RULE_ORDER_TWEAK_CUTOFF.
+                    // Or, we could scan all the rules in the target jar and find an unused number.
+                    // Because rules propagate to subclasses, we'll at least check all the
+                    // super classes of the current class.
+                    throw RavenizerInternalException(
+                        "OOPS: Field $classInternalName.$fieldName uses $order."
+                                + " We can't update it.")
+                }
+                if (order > RULE_ORDER_TWEAK_CUTOFF) {
+                    order -= 1
+                }
+                if (order < -RULE_ORDER_TWEAK_CUTOFF) {
+                    order += 1
+                }
+                super.visit(name, order)
+            }
+        }
+    }
+
+    companion object {
+        fun shouldProcess(classes: ClassNodes, className: String): Boolean {
+            return isTestLookingClass(classes, className)
+        }
+
+        fun maybeApply(
+            className: String,
+            classes: ClassNodes,
+            nextVisitor: ClassVisitor,
+        ): ClassVisitor {
+            if (!shouldProcess(classes, className)) {
+                return nextVisitor
+            } else {
+                return RunnerRewritingAdapter(classes, nextVisitor)
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/adapter/TestRunnerRewritingAdapter.kt b/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/adapter/TestRunnerRewritingAdapter.kt
deleted file mode 100644
index c539908..0000000
--- a/ravenwood/tools/ravenizer/src/com/android/platform/test/ravenwood/ravenizer/adapter/TestRunnerRewritingAdapter.kt
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.platform.test.ravenwood.ravenizer.adapter
-
-import com.android.hoststubgen.asm.ClassNodes
-import com.android.hoststubgen.visitors.OPCODE_VERSION
-import com.android.platform.test.ravenwood.ravenizer.isTestLookingClass
-import org.objectweb.asm.ClassVisitor
-
-/**
- * Class visitor to rewrite the test runner for Ravenwood
- *
- * TODO: Implement it.
- */
-class TestRunnerRewritingAdapter(
-    protected val classes: ClassNodes,
-    nextVisitor: ClassVisitor,
-) : ClassVisitor(OPCODE_VERSION, nextVisitor) {
-   companion object {
-       /**
-        * Returns true if a target class is interesting to this adapter.
-        */
-       fun shouldProcess(classes: ClassNodes, className: String): Boolean {
-            return isTestLookingClass(classes, className)
-       }
-    }
-}