Add SandboxApplication for keeping created contexts in sandbox.

Flag: TEST_ONLY
Bug: 230027385
Test: go/testedequals
Change-Id: I14c277325bd4b3b7cf59ed31dedad338bf1e4440
diff --git a/tests/multivalentTests/src/com/android/launcher3/util/SandboxApplication.kt b/tests/multivalentTests/src/com/android/launcher3/util/SandboxApplication.kt
new file mode 100644
index 0000000..4f9b8c7
--- /dev/null
+++ b/tests/multivalentTests/src/com/android/launcher3/util/SandboxApplication.kt
@@ -0,0 +1,166 @@
+/*
+ * 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.launcher3.util
+
+import android.content.Context
+import android.content.ContextParams
+import android.content.ContextWrapper
+import android.content.pm.ApplicationInfo
+import android.content.res.Configuration
+import android.os.Bundle
+import android.os.IBinder
+import android.os.UserHandle
+import android.view.Display
+import androidx.test.core.app.ApplicationProvider
+import com.android.launcher3.util.LauncherModelHelper.SandboxModelContext
+import com.android.launcher3.util.MainThreadInitializedObject.ObjectSandbox
+import org.junit.Rule
+import org.junit.rules.ExternalResource
+import org.junit.rules.TestRule
+import org.junit.runner.Description
+import org.junit.runners.model.Statement
+
+/**
+ * Sandbox application where created [Context] instances are still sandboxed within it.
+ *
+ * Tests can declare this application as a [Rule], so that it is set up and destroyed automatically.
+ * Alternatively, they can call [init] and [onDestroy] directly. Either way, these need to be called
+ * for it to work and avoid leaks from created singletons.
+ *
+ * The create [Context] APIs construct a `ContextImpl`, which resets the application to the true
+ * application, thus leaving the sandbox. This implementation wraps the created contexts to
+ * propagate this application (see [SandboxApplicationWrapper]).
+ */
+class SandboxApplication private constructor(private val base: SandboxApplicationWrapper) :
+    SandboxModelContext(base), TestRule {
+
+    constructor(
+        base: Context = ApplicationProvider.getApplicationContext()
+    ) : this(SandboxApplicationWrapper(base))
+
+    /**
+     * Initializes the sandbox application propagation logic.
+     *
+     * This function either needs to be called manually or automatically through using [Rule].
+     */
+    fun init() {
+        base.app = this@SandboxApplication
+    }
+
+    /** Returns `this` if [init] was called, otherwise crashes the test. */
+    override fun getApplicationContext(): Context = base.applicationContext
+
+    override fun shouldCleanUpOnDestroy(): Boolean {
+        // Defer to the true application to decide whether to clean up. For instance, we do not want
+        // to cleanup under Robolectric.
+        val app = ApplicationProvider.getApplicationContext<Context>()
+        return if (app is ObjectSandbox) app.shouldCleanUpOnDestroy() else true
+    }
+
+    override fun apply(statement: Statement, description: Description): Statement {
+        return object : ExternalResource() {
+                override fun before() {
+                    base.app = this@SandboxApplication
+                }
+
+                override fun after() = onDestroy()
+            }
+            .apply(statement, description)
+    }
+}
+
+private class SandboxApplicationWrapper(base: Context, var app: Context? = null) :
+    ContextWrapper(base) {
+
+    override fun getApplicationContext(): Context {
+        return checkNotNull(app) { "SandboxApplication accessed before #init() was called." }
+    }
+
+    override fun createPackageContext(packageName: String?, flags: Int): Context {
+        return SandboxApplicationWrapper(super.createPackageContext(packageName, flags), app)
+    }
+
+    override fun createPackageContextAsUser(
+        packageName: String,
+        flags: Int,
+        user: UserHandle,
+    ): Context {
+        return SandboxApplicationWrapper(
+            super.createPackageContextAsUser(packageName, flags, user),
+            app,
+        )
+    }
+
+    override fun createContextAsUser(user: UserHandle, flags: Int): Context {
+        return SandboxApplicationWrapper(super.createContextAsUser(user, flags), app)
+    }
+
+    override fun createApplicationContext(application: ApplicationInfo?, flags: Int): Context {
+        return SandboxApplicationWrapper(super.createApplicationContext(application, flags), app)
+    }
+
+    override fun createContextForSdkInSandbox(sdkInfo: ApplicationInfo, flags: Int): Context {
+        return SandboxApplicationWrapper(super.createContextForSdkInSandbox(sdkInfo, flags), app)
+    }
+
+    override fun createContextForSplit(splitName: String?): Context {
+        return SandboxApplicationWrapper(super.createContextForSplit(splitName), app)
+    }
+
+    override fun createConfigurationContext(overrideConfiguration: Configuration): Context {
+        return SandboxApplicationWrapper(
+            super.createConfigurationContext(overrideConfiguration),
+            app,
+        )
+    }
+
+    override fun createDisplayContext(display: Display): Context {
+        return SandboxApplicationWrapper(super.createDisplayContext(display), app)
+    }
+
+    override fun createDeviceContext(deviceId: Int): Context {
+        return SandboxApplicationWrapper(super.createDeviceContext(deviceId), app)
+    }
+
+    override fun createWindowContext(type: Int, options: Bundle?): Context {
+        return SandboxApplicationWrapper(super.createWindowContext(type, options), app)
+    }
+
+    override fun createWindowContext(display: Display, type: Int, options: Bundle?): Context {
+        return SandboxApplicationWrapper(super.createWindowContext(display, type, options), app)
+    }
+
+    override fun createContext(contextParams: ContextParams): Context {
+        return SandboxApplicationWrapper(super.createContext(contextParams), app)
+    }
+
+    override fun createAttributionContext(attributionTag: String?): Context {
+        return SandboxApplicationWrapper(super.createAttributionContext(attributionTag), app)
+    }
+
+    override fun createCredentialProtectedStorageContext(): Context {
+        return SandboxApplicationWrapper(super.createCredentialProtectedStorageContext(), app)
+    }
+
+    override fun createDeviceProtectedStorageContext(): Context {
+        return SandboxApplicationWrapper(super.createDeviceProtectedStorageContext(), app)
+    }
+
+    override fun createTokenContext(token: IBinder, display: Display): Context {
+        return SandboxApplicationWrapper(super.createTokenContext(token, display), app)
+    }
+}
diff --git a/tests/multivalentTests/src/com/android/launcher3/util/SandboxApplicationTest.kt b/tests/multivalentTests/src/com/android/launcher3/util/SandboxApplicationTest.kt
new file mode 100644
index 0000000..d87a406
--- /dev/null
+++ b/tests/multivalentTests/src/com/android/launcher3/util/SandboxApplicationTest.kt
@@ -0,0 +1,78 @@
+/*
+ * 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.launcher3.util
+
+import android.content.Context
+import android.hardware.display.DisplayManager
+import android.view.Display
+import android.view.Display.DEFAULT_DISPLAY
+import android.view.WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY
+import com.google.common.truth.Truth.assertThat
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(LauncherMultivalentJUnit::class)
+class SandboxApplicationTest {
+    @get:Rule val app = SandboxApplication()
+
+    private val display: Display
+        get() {
+            return checkNotNull(app.getSystemService(DisplayManager::class.java))
+                .getDisplay(DEFAULT_DISPLAY)
+        }
+
+    @Test
+    fun testCreateDisplayContext_isSandboxed() {
+        val displayContext = app.createDisplayContext(display)
+        assertThat(displayContext.applicationContext).isEqualTo(app)
+    }
+
+    @Test
+    fun testCreateWindowContext_fromSandboxedDisplayContext_isSandboxed() {
+        val displayContext = app.createDisplayContext(display)
+        val nestedContext = displayContext.createWindowContext(TYPE_APPLICATION_OVERLAY, null)
+        assertThat(nestedContext.applicationContext).isEqualTo(app)
+    }
+
+    @Test(expected = IllegalStateException::class)
+    fun testGetApplicationContext_beforeManualInit_throwsException() {
+        val manualApp = SandboxApplication()
+        assertThat(manualApp.applicationContext).isEqualTo(manualApp)
+    }
+
+    @Test
+    fun testGetApplicationContext_afterManualInit_isApplication() {
+        SandboxApplication().run {
+            init()
+            assertThat(applicationContext).isEqualTo(this)
+            onDestroy()
+        }
+    }
+
+    @Test
+    fun testGetObject_objectCreatesDisplayContext_isSandboxed() {
+        class TestSingleton(context: Context) : SafeCloseable {
+            override fun close() = Unit
+
+            val displayContext = context.createDisplayContext(display)
+        }
+
+        val displayContext = MainThreadInitializedObject { TestSingleton(it) }[app].displayContext
+        assertThat(displayContext.applicationContext).isEqualTo(app)
+    }
+}