WM Tests: Use a separate WindowManager instance per test
Fixes a bunch of flakes, where the WindowManagerService instance
was reused between tests, which caused delayed callbacks from a
previous test affecting state of a future test.
Also introduces a DexmakerShareClassLoaderRule to manage
the 'dexmaker.share_classloader' property instead of sprinkling
error prone System.setProperty() invocations all over the tests.
Change-Id: Ic9445d1b2cef594e79365c425632aabced6343a9
Fixes: 76111404
Fixes: 75991352
Fixes: 75991878
Fixes: 75992153
Test: atest services/tests/servicestests DexmakerShareClassLoaderRuleTest packages/SystemUI/tests packages/SystemUI/shared/tests
diff --git a/tests/testables/src/android/testing/DexmakerShareClassLoaderRule.java b/tests/testables/src/android/testing/DexmakerShareClassLoaderRule.java
new file mode 100644
index 0000000..1b8e58c
--- /dev/null
+++ b/tests/testables/src/android/testing/DexmakerShareClassLoaderRule.java
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2018 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.testing;
+
+import android.util.Log;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+import java.util.ConcurrentModificationException;
+
+
+/**
+ * Runs the test such that mocks created in it don't use a dedicated classloader.
+ *
+ * This allows mocking package-private methods.
+ *
+ * WARNING: This is absolutely incompatible with running tests in parallel!
+ */
+public class DexmakerShareClassLoaderRule implements TestRule {
+
+ private static final String TAG = "ShareClassloaderRule";
+ @VisibleForTesting
+ static final String DEXMAKER_SHARE_CLASSLOADER_PROPERTY = "dexmaker.share_classloader";
+
+ private static Thread sOwningThread = null;
+
+ @Override
+ public Statement apply(Statement base, Description description) {
+ return apply(base::evaluate).toStatement();
+ }
+
+ /**
+ * Runs the runnable such that mocks created in it don't use a dedicated classloader.
+ *
+ * This allows mocking package-private methods.
+ *
+ * WARNING: This is absolutely incompatible with running tests in parallel!
+ */
+ public static void runWithDexmakerShareClassLoader(Runnable r) {
+ apply(r::run).run();
+ }
+
+ /**
+ * Returns a statement that first makes sure that only one thread at the time is modifying
+ * the property. Then actually sets the property, and runs the statement.
+ */
+ private static <T extends Throwable> ThrowingRunnable<T> apply(ThrowingRunnable<T> r) {
+ return wrapInMutex(wrapInSetAndClearProperty(r));
+ }
+
+ private static <T extends Throwable> ThrowingRunnable<T> wrapInSetAndClearProperty(
+ ThrowingRunnable<T> r) {
+ return () -> {
+ final String previousValue = System.getProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY);
+ try {
+ System.setProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY, "true");
+ r.run();
+ } finally {
+ if (previousValue != null) {
+ System.setProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY, previousValue);
+ } else {
+ System.clearProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY);
+ }
+ }
+ };
+ }
+
+ /**
+ * Runs the given statement, and while doing so prevents other threads from running statements.
+ */
+ private static <T extends Throwable> ThrowingRunnable<T> wrapInMutex(ThrowingRunnable<T> r) {
+ return () -> {
+ final boolean isOwner;
+ synchronized (DexmakerShareClassLoaderRule.class) {
+ isOwner = (sOwningThread == null);
+ if (isOwner) {
+ sOwningThread = Thread.currentThread();
+ } else if (sOwningThread != Thread.currentThread()) {
+ final RuntimeException e = new ConcurrentModificationException(
+ "Tried to set dexmaker.share_classloader from " + Thread.currentThread()
+ + ", but was already set from " + sOwningThread);
+ // Also log in case exception gets swallowed.
+ Log.e(TAG, e.getMessage(), e);
+ throw e;
+ }
+ }
+ try {
+ r.run();
+ } finally {
+ synchronized (DexmakerShareClassLoaderRule.class) {
+ if (isOwner) {
+ sOwningThread = null;
+ }
+ }
+ }
+ };
+ }
+
+ private interface ThrowingRunnable<T extends Throwable> {
+ void run() throws T;
+
+ default Statement toStatement() {
+ return new Statement() {
+ @Override
+ public void evaluate() throws Throwable {
+ ThrowingRunnable.this.run();
+ }
+ };
+ }
+ }
+}