Verifying that workspace looks correct at the end of the test.

I hope that this will lock bugs like b/298114205 in the test that created the bad condition, not the next one.

Bug: 298114205
Test: presubmit
Flag: N/A
Change-Id: If9b48fb5159fc35948607a99f87199d5a32e64d6
diff --git a/tests/Android.bp b/tests/Android.bp
index 654edad..d828fdf 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -58,6 +58,7 @@
       "src/com/android/launcher3/util/rule/SamplerRule.java",
       "src/com/android/launcher3/util/rule/ScreenRecordRule.java",
       "src/com/android/launcher3/util/rule/ShellCommandRule.java",
+      "src/com/android/launcher3/util/rule/TestIsolationRule.java",
       "src/com/android/launcher3/util/rule/TestStabilityRule.java",
       "src/com/android/launcher3/util/rule/TISBindRule.java",
       "src/com/android/launcher3/util/viewcapture_analysis/*.java",
diff --git a/tests/src/com/android/launcher3/ui/AbstractLauncherUiTest.java b/tests/src/com/android/launcher3/ui/AbstractLauncherUiTest.java
index 3e5d717..3f763c3 100644
--- a/tests/src/com/android/launcher3/ui/AbstractLauncherUiTest.java
+++ b/tests/src/com/android/launcher3/ui/AbstractLauncherUiTest.java
@@ -18,7 +18,6 @@
 import static androidx.test.InstrumentationRegistry.getInstrumentation;
 
 import static com.android.launcher3.testing.shared.TestProtocol.ICON_MISSING;
-import static com.android.launcher3.ui.TaplTestsLauncher3.getAppPackageName;
 import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;
 
 import static org.junit.Assert.assertEquals;
@@ -68,6 +67,7 @@
 import com.android.launcher3.util.rule.SamplerRule;
 import com.android.launcher3.util.rule.ScreenRecordRule;
 import com.android.launcher3.util.rule.ShellCommandRule;
+import com.android.launcher3.util.rule.TestIsolationRule;
 import com.android.launcher3.util.rule.TestStabilityRule;
 import com.android.launcher3.util.rule.ViewCaptureRule;
 
@@ -210,7 +210,8 @@
         final RuleChain inner = RuleChain
                 .outerRule(new PortraitLandscapeRunner(this))
                 .around(new FailureWatcher(mLauncher, viewCaptureRule::getViewCaptureData))
-                .around(viewCaptureRule);
+                .around(viewCaptureRule)
+                .around(new TestIsolationRule(mLauncher));
 
         return TestHelpers.isInLauncherProcess()
                 ? RuleChain.outerRule(ShellCommandRule.setDefaultLauncher()).around(inner)
diff --git a/tests/src/com/android/launcher3/util/rule/TestIsolationRule.java b/tests/src/com/android/launcher3/util/rule/TestIsolationRule.java
new file mode 100644
index 0000000..c1f9d40
--- /dev/null
+++ b/tests/src/com/android/launcher3/util/rule/TestIsolationRule.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2023 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.launcher3.util.rule;
+
+import androidx.annotation.NonNull;
+import androidx.test.InstrumentationRegistry;
+import androidx.test.uiautomator.UiDevice;
+
+import com.android.launcher3.tapl.LauncherInstrumentation;
+import com.android.launcher3.ui.AbstractLauncherUiTest;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+/**
+ * Isolates tests from some of the state created by the previous test.
+ */
+public class TestIsolationRule implements TestRule {
+    final LauncherInstrumentation mLauncher;
+
+    public TestIsolationRule(LauncherInstrumentation launcher) {
+        mLauncher = launcher;
+    }
+
+    @NonNull
+    @Override
+    public Statement apply(@NonNull Statement base, @NonNull Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                base.evaluate();
+                // Make sure that Launcher workspace looks correct.
+
+                UiDevice.getInstance(InstrumentationRegistry.getInstrumentation()).pressHome();
+                AbstractLauncherUiTest.checkDetectedLeaks(mLauncher);
+            }
+        };
+    }
+}