Added executor framework to sync prod and tests

+ Use a TestableExecutor in the production code to allow tests to
sync up and block so the state of the system can be tested. In the
tests the executor can wait until the production code hits a
milestone to ensure that the system is in a proper state for testing.

+ The current implementation only attempts to synchronize between one
production thread and one test thread. Extend the TestableExecutor
interface to perform additional synchronization.

Change-Id: Ie6fc64392e402330ab66c6f2cd0ec22200ebbdea

3 files changed, 153 insertions, 0 deletions

diff --git a/InCallUI/src/com/android/incallui/async/PausableExecutor.java b/InCallUI/src/com/android/incallui/async/PausableExecutor.java
new file mode 100644
index 000000000..fdeef360c
--- /dev/null
+++ b/InCallUI/src/com/android/incallui/async/PausableExecutor.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2016 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.incallui.async;
+
+import com.android.contacts.common.testing.NeededForTesting;
+
+import java.util.concurrent.Executor;
+
+/**
+ * Executor that can be used to easily synchronize testing and production code. Production code
+ * should call {@link #milestone()} at points in the code where the state of the system is worthy of
+ * testing. In a test scenario, this method will pause execution until the test acknowledges the
+ * milestone through the use of {@link #ackMilestoneForTesting()}.
+ */
+public interface PausableExecutor extends Executor {
+
+    /**
+     * Method called from asynchronous production code to inform this executor that it has
+     * reached a point that puts the system into a state worth testing. TestableExecutors intended
+     * for use in a testing environment should cause the calling thread to block. In the production
+     * environment this should be a no-op.
+     */
+    void milestone();
+
+    /**
+     * Method called from the test code to inform this executor that the state of the production
+     * system at the current milestone has been sufficiently tested. Every milestone must be
+     * acknowledged.
+     */
+    @NeededForTesting
+    void ackMilestoneForTesting();
+
+    /**
+     * Method called from the test code to block until a milestone has been reached in the
+     * production code.
+     */
+    @NeededForTesting
+    void awaitMilestoneForTesting() throws InterruptedException;
+}
diff --git a/InCallUI/src/com/android/incallui/async/PausableExecutorImpl.java b/InCallUI/src/com/android/incallui/async/PausableExecutorImpl.java
new file mode 100644
index 000000000..e493feb3d
--- /dev/null
+++ b/InCallUI/src/com/android/incallui/async/PausableExecutorImpl.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2016 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.incallui.async;
+
+import java.util.concurrent.Executors;
+
+/**
+ * {@link PausableExecutor} intended for use in production environments.
+ */
+public class PausableExecutorImpl implements PausableExecutor {
+
+    @Override
+    public void milestone() {}
+
+    @Override
+    public void ackMilestoneForTesting() {}
+
+    @Override
+    public void awaitMilestoneForTesting() {}
+
+    @Override
+    public void execute(Runnable command) {
+        Executors.newSingleThreadExecutor().execute(command);
+    }
+}
diff --git a/InCallUI/tests/src/com/android/incallui/async/SingleProdThreadExecutor.java b/InCallUI/tests/src/com/android/incallui/async/SingleProdThreadExecutor.java
new file mode 100644
index 000000000..ee27862b3
--- /dev/null
+++ b/InCallUI/tests/src/com/android/incallui/async/SingleProdThreadExecutor.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2016 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.incallui.async;
+
+import java.util.concurrent.Executors;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * {@link PausableExecutor} for use in tests. It is intended to be used between one test thread
+ * and one prod thread.
+ */
+@ThreadSafe
+public final class SingleProdThreadExecutor implements PausableExecutor {
+
+    private int mMilestonesReached;
+    private int mMilestonesAcked;
+
+    @Override
+    public synchronized void milestone() {
+        ++mMilestonesReached;
+        notify();
+        while (mMilestonesReached > mMilestonesAcked) {
+            try {
+                wait();
+            } catch (InterruptedException e) {}
+        }
+    }
+
+    @Override
+    public synchronized void ackMilestoneForTesting() {
+        ++mMilestonesAcked;
+        notify();
+    }
+
+    @Override
+    public synchronized void awaitMilestoneForTesting() throws InterruptedException {
+        while (mMilestonesReached <= mMilestonesAcked) {
+            wait();
+        }
+    }
+
+    @Override
+    public synchronized void execute(Runnable command) {
+        Executors.newSingleThreadExecutor().execute(command);
+    }
+}