Snap for 7984612 from e9461ba5694bde2aeaf4f215c32ac62f48096874 to mainline-resolv-releaseandroid-mainline-12.0.0_r80android-mainline-12.0.0_r65

Change-Id: I49f39fcec1ca0b83e464f19c2519d01832429dab

10 files changed, 1314 insertions, 0 deletions

diff --git a/java/com/android/modules/utils/testing/Android.bp b/java/com/android/modules/utils/testing/Android.bp
index 28bd82c..d39bf3c 100644
--- a/java/com/android/modules/utils/testing/Android.bp
+++ b/java/com/android/modules/utils/testing/Android.bp
@@ -27,3 +27,35 @@ java_library {
     min_sdk_version: "29",
     visibility: ["//visibility:public"],
 }
+
+// Depend on modules-utils-testable-device-config-defaults instead of this library.
+java_library {
+    name: "modules-utils-testable-device-config",
+    srcs: [
+        "StaticMockFixture.java",
+        "StaticMockFixtureRule.java",
+        "TestableDeviceConfig.java",
+    ],
+    static_libs: [
+        "androidx.test.rules",
+        "mockito-target-extended-minus-junit4",
+    ],
+    sdk_version: "module_current",
+    min_sdk_version: "29",
+    visibility: ["//visibility:public"],
+}
+
+// Utility for mocking DeviceConfig and other device state.
+// In order to use these utils successfully, both Java code and native libraries will be required.
+// If your code is in a library, you will have to depend on these defaults both in the library as
+// well as in the android_test that it gets linked into.
+// You will also need to specify android:debuggable="true" in the test's manifest.
+java_defaults {
+    name: "modules-utils-testable-device-config-defaults",
+    static_libs: ["modules-utils-testable-device-config"],
+    jni_libs: [
+        "libdexmakerjvmtiagent",
+        "libstaticjvmtiagent",
+    ],
+    defaults_visibility: ["//visibility:public"],
+}
diff --git a/java/com/android/modules/utils/testing/StaticMockFixture.java b/java/com/android/modules/utils/testing/StaticMockFixture.java
new file mode 100644
index 0000000..d800b4f
--- /dev/null
+++ b/java/com/android/modules/utils/testing/StaticMockFixture.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2019 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.modules.utils.testing;
+
+
+import com.android.dx.mockito.inline.extended.StaticMockitoSession;
+import com.android.dx.mockito.inline.extended.StaticMockitoSessionBuilder;
+
+/**
+ * Provides support for a set of static mocks for use within a single shared
+ * {@link StaticMockitoSession}.
+ */
+public interface StaticMockFixture {
+    /**
+     * Adds any required mock or spy classes managed by this {@link StaticMockFixture} to the
+     * {@link StaticMockitoSessionBuilder} provided.
+     *
+     * Call this to set up the classes that this expects to be mocked, by adding them to the
+     * {@link StaticMockitoSessionBuilder} using
+     * {@link StaticMockitoSessionBuilder#mockStatic(Class)},
+     * {@link StaticMockitoSessionBuilder#spyStatic(Class)} or similar as appropriate.
+     *
+     * @param sessionBuilder the {@link StaticMockitoSessionBuilder} to which the classes should be
+     *                       added to mock, spy, or otherwise as required
+     * @return sessionBuilder, to allow for fluent programming
+     */
+    StaticMockitoSessionBuilder setUpMockedClasses(StaticMockitoSessionBuilder sessionBuilder);
+
+    /**
+     * Configures the behaviours of any mock or spy classes managed by this
+     * {@link StaticMockFixture}.
+     *
+     * Call this after {@link StaticMockitoSessionBuilder#startMocking()} has been called.
+     * This sets up any default behaviors for the mocks, spys, etc.
+     */
+    void setUpMockBehaviors();
+
+    /**
+     * Tear everything down.
+     */
+    void tearDown();
+}
diff --git a/java/com/android/modules/utils/testing/StaticMockFixtureRule.java b/java/com/android/modules/utils/testing/StaticMockFixtureRule.java
new file mode 100644
index 0000000..0cdc9a2
--- /dev/null
+++ b/java/com/android/modules/utils/testing/StaticMockFixtureRule.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2019 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.modules.utils.testing;
+
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.mockitoSession;
+
+import com.android.dx.mockito.inline.extended.StaticMockitoSession;
+import com.android.dx.mockito.inline.extended.StaticMockitoSessionBuilder;
+
+import org.junit.AssumptionViolatedException;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+import org.mockito.quality.Strictness;
+
+import java.util.function.Supplier;
+
+/**
+ * <p>StaticMockFixtureRule is a {@link TestRule} that wraps one or more {@link StaticMockFixture}s
+ * to set them up and tear it down automatically. This works well when you have no other static
+ * mocks than the ones supported by their respective {@link StaticMockFixture}s.</p>
+ *
+ * <p>StaticMockFixtureRule should be defined as a rule on your test so it can clean up after
+ * itself. Like the following:</p>
+ * <pre class="prettyprint">
+*  public final StaticMockFixture mStaticMockFixtures = ...;
+ * &#064;Rule
+ * public final StaticMockFixtureRule mStaticMockFixtureRule =
+ *     new StaticMockFixtureRule(mStaticMockFixtures);
+ * </pre>
+ */
+public class StaticMockFixtureRule implements TestRule {
+    private StaticMockitoSession mMockitoSession;
+    private StaticMockFixture[] mStaticMockFixtures;
+    private Supplier<? extends StaticMockFixture>[] mSupplier;
+
+    /**
+     * Constructs a StaticMockFixtureRule that always uses the same {@link StaticMockFixture}
+     * instance(s).
+     *
+     * @param staticMockFixtures the {@link StaticMockFixture}(s) to use.
+     */
+    public StaticMockFixtureRule(StaticMockFixture... staticMockFixtures) {
+        mStaticMockFixtures = staticMockFixtures;
+        mSupplier = null;
+    }
+
+    /**
+     * Constructs a StaticMockFixtureRule that retrieves a new {@link StaticMockFixture} instance
+     * from one or more {@link Supplier<? extends   StaticMockFixture  >}s for each test invocation.
+     *
+     * @param supplier the {@link Supplier<? extends   StaticMockFixture  >}(s) that will supply the
+     * {@link StaticMockFixture}(s).
+     */
+    @SafeVarargs
+    public StaticMockFixtureRule(Supplier<? extends StaticMockFixture>... supplier) {
+        mStaticMockFixtures = null;
+        mSupplier = supplier;
+    }
+
+    @Override
+    public Statement apply(Statement base, Description description) {
+        StaticMockitoSessionBuilder sessionBuilder = getSessionBuilder();
+
+        if (mSupplier != null) {
+            mStaticMockFixtures = new StaticMockFixture[mSupplier.length];
+            for (int i = 0; i < mSupplier.length; i++) {
+                mStaticMockFixtures[i] = mSupplier[i].get();
+            }
+        }
+
+        for (int i = 0; i < mStaticMockFixtures.length; i++) {
+            sessionBuilder = mStaticMockFixtures[i].setUpMockedClasses(sessionBuilder);
+        }
+
+        mMockitoSession = sessionBuilder.startMocking();
+
+        for (int i = 0; i < mStaticMockFixtures.length; i++) {
+            mStaticMockFixtures[i].setUpMockBehaviors();
+        }
+
+        return new TestWatcher() {
+            @Override
+            protected void succeeded(Description description) {
+                tearDown(null);
+            }
+
+            @Override
+            protected void skipped(AssumptionViolatedException e, Description description) {
+                tearDown(e);
+            }
+
+            @Override
+            protected void failed(Throwable e, Description description) {
+                tearDown(e);
+            }
+        }.apply(base, description);
+    }
+
+    /**
+     * This allows overriding the creation of the builder for a new {@link StaticMockitoSession}.
+     * Mainly for testing, but also useful if you have other requirements for the session.
+     *
+     * @return a new {@link StaticMockitoSessionBuilder}.
+     */
+    public StaticMockitoSessionBuilder getSessionBuilder() {
+        return mockitoSession().strictness(Strictness.LENIENT);
+    }
+
+    private void tearDown(Throwable e) {
+        mMockitoSession.finishMocking(e);
+
+        for (int i = mStaticMockFixtures.length - 1; i >= 0; i--) {
+            mStaticMockFixtures[i].tearDown();
+            if (mSupplier != null) {
+                mStaticMockFixtures[i] = null;
+            }
+        }
+
+        if (mSupplier != null) {
+            mStaticMockFixtures = null;
+        }
+
+        mMockitoSession = null;
+    }
+}
diff --git a/java/com/android/modules/utils/testing/TestableDeviceConfig.java b/java/com/android/modules/utils/testing/TestableDeviceConfig.java
new file mode 100644
index 0000000..8f62e03
--- /dev/null
+++ b/java/com/android/modules/utils/testing/TestableDeviceConfig.java
@@ -0,0 +1,258 @@
+/*
+ * Copyright (C) 2019 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.modules.utils.testing;
+
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.doAnswer;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.anyFloat;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.nullable;
+import static org.mockito.Mockito.when;
+
+import android.provider.DeviceConfig;
+import android.provider.DeviceConfig.Properties;
+import android.util.ArrayMap;
+import android.util.Pair;
+
+import com.android.dx.mockito.inline.extended.StaticMockitoSessionBuilder;
+
+import org.junit.rules.TestRule;
+import org.mockito.ArgumentMatchers;
+import org.mockito.Mockito;
+import org.mockito.stubbing.Answer;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executor;
+
+/**
+ * TestableDeviceConfig is a {@link StaticMockFixture} that uses ExtendedMockito to replace the real
+ * implementation of DeviceConfig with essentially a local HashMap in the callers process. This
+ * allows for unit testing that do not modify the real DeviceConfig on the device at all.
+ */
+public final class TestableDeviceConfig implements StaticMockFixture {
+
+    private Map<DeviceConfig.OnPropertiesChangedListener, Pair<String, Executor>>
+            mOnPropertiesChangedListenerMap = new HashMap<>();
+    private Map<String, String> mKeyValueMap = new ConcurrentHashMap<>();
+
+    /**
+     * Clears out all local overrides.
+     */
+    public void clearDeviceConfig() {
+        mKeyValueMap.clear();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public StaticMockitoSessionBuilder setUpMockedClasses(
+            StaticMockitoSessionBuilder sessionBuilder) {
+        sessionBuilder.spyStatic(DeviceConfig.class);
+        return sessionBuilder;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void setUpMockBehaviors() {
+        doAnswer((Answer<Void>) invocationOnMock -> {
+            String namespace = invocationOnMock.getArgument(0);
+            Executor executor = invocationOnMock.getArgument(1);
+            DeviceConfig.OnPropertiesChangedListener onPropertiesChangedListener =
+                    invocationOnMock.getArgument(2);
+            mOnPropertiesChangedListenerMap.put(
+                    onPropertiesChangedListener, new Pair<>(namespace, executor));
+            return null;
+        }).when(() -> DeviceConfig.addOnPropertiesChangedListener(
+                anyString(), any(Executor.class),
+                any(DeviceConfig.OnPropertiesChangedListener.class)));
+
+        doAnswer((Answer<Boolean>) invocationOnMock -> {
+                    String namespace = invocationOnMock.getArgument(0);
+                    String name = invocationOnMock.getArgument(1);
+                    String value = invocationOnMock.getArgument(2);
+                    mKeyValueMap.put(getKey(namespace, name), value);
+                    for (DeviceConfig.OnPropertiesChangedListener listener :
+                            mOnPropertiesChangedListenerMap.keySet()) {
+                        if (namespace.equals(mOnPropertiesChangedListenerMap.get(listener).first)) {
+                            mOnPropertiesChangedListenerMap.get(listener).second.execute(
+                                    () -> listener.onPropertiesChanged(
+                                            getProperties(namespace, name, value)));
+                        }
+                    }
+                    return true;
+                }
+        ).when(() -> DeviceConfig.setProperty(anyString(), anyString(), anyString(), anyBoolean()));
+
+        doAnswer((Answer<String>) invocationOnMock -> {
+            String namespace = invocationOnMock.getArgument(0);
+            String name = invocationOnMock.getArgument(1);
+            return mKeyValueMap.get(getKey(namespace, name));
+        }).when(() -> DeviceConfig.getProperty(anyString(), anyString()));
+
+        doAnswer((Answer<Properties>) invocationOnMock -> {
+            String namespace = invocationOnMock.getArgument(0);
+            final int varargStartIdx = 1;
+            Map<String, String> keyValues = new ArrayMap<>();
+            if (invocationOnMock.getArguments().length == varargStartIdx) {
+                mKeyValueMap.entrySet().forEach(entry -> {
+                    Pair<String, String> nameSpaceAndName = getNameSpaceAndName(entry.getKey());
+                    if (!nameSpaceAndName.first.equals(namespace)) {
+                        return;
+                    }
+                    keyValues.put(nameSpaceAndName.second.toLowerCase(), entry.getValue());
+                });
+            } else {
+                for (int i = varargStartIdx; i < invocationOnMock.getArguments().length; ++i) {
+                    String name = invocationOnMock.getArgument(i);
+                    keyValues.put(name.toLowerCase(), mKeyValueMap.get(getKey(namespace, name)));
+                }
+            }
+            return getProperties(namespace, keyValues);
+        }).when(() -> DeviceConfig.getProperties(anyString(), ArgumentMatchers.<String>any()));
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void tearDown() {
+        clearDeviceConfig();
+        mOnPropertiesChangedListenerMap.clear();
+    }
+
+    private static String getKey(String namespace, String name) {
+        return namespace + "/" + name;
+    }
+
+    private Pair<String, String> getNameSpaceAndName(String key) {
+        final String[] values = key.split("/");
+        return Pair.create(values[0], values[1]);
+    }
+
+    private Properties getProperties(String namespace, String name, String value) {
+        return getProperties(namespace, Collections.singletonMap(name.toLowerCase(), value));
+    }
+
+    private Properties getProperties(String namespace, Map<String, String> keyValues) {
+        Properties properties = Mockito.mock(Properties.class);
+        when(properties.getNamespace()).thenReturn(namespace);
+        when(properties.getKeyset()).thenReturn(keyValues.keySet());
+        when(properties.getBoolean(anyString(), anyBoolean())).thenAnswer(
+                invocation -> {
+                    String key = invocation.getArgument(0);
+                    boolean defaultValue = invocation.getArgument(1);
+                    final String value = keyValues.get(key.toLowerCase());
+                    if (value != null) {
+                        return Boolean.parseBoolean(value);
+                    } else {
+                        return defaultValue;
+                    }
+                }
+        );
+        when(properties.getFloat(anyString(), anyFloat())).thenAnswer(
+                invocation -> {
+                    String key = invocation.getArgument(0);
+                    float defaultValue = invocation.getArgument(1);
+                    final String value = keyValues.get(key.toLowerCase());
+                    if (value != null) {
+                        try {
+                            return Float.parseFloat(value);
+                        } catch (NumberFormatException e) {
+                            return defaultValue;
+                        }
+                    } else {
+                        return defaultValue;
+                    }
+                }
+        );
+        when(properties.getInt(anyString(), anyInt())).thenAnswer(
+                invocation -> {
+                    String key = invocation.getArgument(0);
+                    int defaultValue = invocation.getArgument(1);
+                    final String value = keyValues.get(key.toLowerCase());
+                    if (value != null) {
+                        try {
+                            return Integer.parseInt(value);
+                        } catch (NumberFormatException e) {
+                            return defaultValue;
+                        }
+                    } else {
+                        return defaultValue;
+                    }
+                }
+        );
+        when(properties.getLong(anyString(), anyLong())).thenAnswer(
+                invocation -> {
+                    String key = invocation.getArgument(0);
+                    long defaultValue = invocation.getArgument(1);
+                    final String value = keyValues.get(key.toLowerCase());
+                    if (value != null) {
+                        try {
+                            return Long.parseLong(value);
+                        } catch (NumberFormatException e) {
+                            return defaultValue;
+                        }
+                    } else {
+                        return defaultValue;
+                    }
+                }
+        );
+        when(properties.getString(anyString(), nullable(String.class))).thenAnswer(
+                invocation -> {
+                    String key = invocation.getArgument(0);
+                    String defaultValue = invocation.getArgument(1);
+                    final String value = keyValues.get(key.toLowerCase());
+                    if (value != null) {
+                        return value;
+                    } else {
+                        return defaultValue;
+                    }
+                }
+        );
+
+        return properties;
+    }
+
+    /**
+     * <p>TestableDeviceConfigRule is a {@link TestRule} that wraps a {@link TestableDeviceConfig}
+     * to set it up and tear it down automatically. This works well when you have no other static
+     * mocks.</p>
+     *
+     * <p>TestableDeviceConfigRule should be defined as a rule on your test so it can clean up after
+     * itself. Like the following:</p>
+     * <pre class="prettyprint">
+     * &#064;Rule
+     * public final TestableDeviceConfigRule mTestableDeviceConfigRule =
+     *     new TestableDeviceConfigRule();
+     * </pre>
+     */
+    public static class TestableDeviceConfigRule extends StaticMockFixtureRule {
+        public TestableDeviceConfigRule() {
+            super(TestableDeviceConfig::new);
+        }
+    }
+}
diff --git a/javatests/com/android/modules/utils/testing/Android.bp b/javatests/com/android/modules/utils/testing/Android.bp
new file mode 100644
index 0000000..89f7797
--- /dev/null
+++ b/javatests/com/android/modules/utils/testing/Android.bp
@@ -0,0 +1,49 @@
+//
+// Copyright (C) 2021 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 {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+android_test {
+    name: "ModulesUtilsTestingTests",
+
+    sdk_version: "module_current",
+    min_sdk_version: "29",
+
+    defaults: [
+        "modules-utils-testable-device-config-defaults",
+    ],
+
+    srcs: ["*.java"],
+
+    static_libs: [
+        "androidx.test.core",
+        "androidx.test.runner",
+        "androidx.test.rules",
+        "platform-test-annotations",
+        "truth-prebuilt",
+    ],
+
+    libs: [
+        "android.test.mock",
+        "android.test.runner",
+    ],
+
+    test_suites: [
+        "general-tests",
+        "mts",
+    ],
+}
diff --git a/javatests/com/android/modules/utils/testing/AndroidManifest.xml b/javatests/com/android/modules/utils/testing/AndroidManifest.xml
new file mode 100644
index 0000000..d1077ce
--- /dev/null
+++ b/javatests/com/android/modules/utils/testing/AndroidManifest.xml
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2021 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.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.modules.utils.testing">
+
+    <application android:debuggable="true">
+        <uses-library android:name="android.test.runner" />
+    </application>
+
+    <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+            android:targetPackage="com.android.modules.utils.testing"/>
+</manifest>
diff --git a/javatests/com/android/modules/utils/testing/MultipleStaticMocksTest.java b/javatests/com/android/modules/utils/testing/MultipleStaticMocksTest.java
new file mode 100644
index 0000000..b925a6c
--- /dev/null
+++ b/javatests/com/android/modules/utils/testing/MultipleStaticMocksTest.java
@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2019 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.modules.utils.testing;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.dx.mockito.inline.extended.ExtendedMockito;
+import com.android.dx.mockito.inline.extended.StaticMockitoSessionBuilder;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class MultipleStaticMocksTest {
+    @Rule
+    public StaticMockFixtureRule mStaticMockFixtureRule =
+            new StaticMockFixtureRule(AB::new, CD::new);
+
+    private List<String> mCollected;
+
+    @Test
+    public void testMultipleStaticMocks() throws Exception {
+        mCollected = new ArrayList<>();
+        int n = 0;
+
+        A.a();
+        n = verifyCollected(n, "A.a");
+
+        D.b();
+        n = verifyCollected(n, "D.b");
+
+        C.b();
+        n = verifyCollected(n, "C.b");
+
+        B.a();
+        n = verifyCollected(n, "B.a");
+    }
+
+    private int verifyCollected(int n, String... last) {
+        assertThat(mCollected).hasSize(n + last.length);
+        assertThat(mCollected.subList(n, mCollected.size()))
+                .containsExactlyElementsIn(last).inOrder();
+        return n + last.length;
+    }
+
+    private static class A {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    private static class B {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    private static class C {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    private static class D {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    /**
+     * AB StaticMockFixture class that handles two mocked classes, {@link A} and {@link B}.
+     */
+    private class AB implements StaticMockFixture {
+        @Override
+        public StaticMockitoSessionBuilder setUpMockedClasses(
+                StaticMockitoSessionBuilder sessionBuilder) {
+            sessionBuilder.spyStatic(A.class);
+            sessionBuilder.spyStatic(B.class);
+            return sessionBuilder;
+        }
+
+        @Override
+        public void setUpMockBehaviors() {
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("A.a");
+                return null;
+            }).when(A::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("A.b");
+                return null;
+            }).when(A::b);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("B.a");
+                return null;
+            }).when(B::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("B.b");
+                return null;
+            }).when(B::b);
+        }
+
+        @Override
+        public void tearDown() {
+
+        }
+    }
+
+    /**
+     * AB StaticMockFixture class that handles two mocked classes, {@link C} and {@link D}.
+     */
+    private class CD implements StaticMockFixture {
+        @Override
+        public StaticMockitoSessionBuilder setUpMockedClasses(
+                StaticMockitoSessionBuilder sessionBuilder) {
+            sessionBuilder.spyStatic(C.class);
+            sessionBuilder.spyStatic(D.class);
+            return sessionBuilder;
+        }
+
+        @Override
+        public void setUpMockBehaviors() {
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("C.a");
+                return null;
+            }).when(C::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("C.b");
+                return null;
+            }).when(C::b);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("D.a");
+                return null;
+            }).when(D::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("D.b");
+                return null;
+            }).when(D::b);
+        }
+
+        @Override
+        public void tearDown() {
+
+        }
+    }
+}
diff --git a/javatests/com/android/modules/utils/testing/StaticMockFixtureRuleTest.java b/javatests/com/android/modules/utils/testing/StaticMockFixtureRuleTest.java
new file mode 100644
index 0000000..7336761
--- /dev/null
+++ b/javatests/com/android/modules/utils/testing/StaticMockFixtureRuleTest.java
@@ -0,0 +1,258 @@
+/*
+ * Copyright (C) 2019 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.modules.utils.testing;
+
+import static org.junit.Assert.fail;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+import static org.mockito.quality.Strictness.LENIENT;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.dx.mockito.inline.extended.StaticMockitoSession;
+import com.android.dx.mockito.inline.extended.StaticMockitoSessionBuilder;
+
+import org.junit.After;
+import org.junit.AssumptionViolatedException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.Description;
+import org.junit.runner.RunWith;
+import org.junit.runners.model.Statement;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoSession;
+
+import java.util.function.Supplier;
+
+/** Tests that StaticMockFixture manages fixtures and suppliers correctly. */
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class StaticMockFixtureRuleTest {
+    private MockitoSession mMockitoSession;
+
+    @Mock private StaticMockitoSessionBuilder mSessionBuilder;
+    @Mock private StaticMockitoSession mSession;
+    @Mock private StaticMockFixture mA1;
+    @Mock private StaticMockFixture mB1;
+    @Mock private StaticMockFixture mA2;
+    @Mock private StaticMockFixture mB2;
+    @Mock private Supplier<StaticMockFixture> mSupplyA;
+    @Mock private Supplier<StaticMockFixture> mSupplyB;
+    @Mock private Statement mStatement;
+    @Mock private Statement mSkipStatement;
+    @Mock private Statement mThrowStatement;
+    @Mock private Description mDescription;
+
+    @Before
+    public void setUp() throws Throwable {
+        mMockitoSession = Mockito.mockitoSession()
+                .strictness(LENIENT)
+                .initMocks(this)
+                .startMocking();
+        prepareMockBehaviours();
+    }
+
+    @After
+    public void tearDown() {
+        mMockitoSession.finishMocking();
+    }
+
+    private void prepareFixtureMocks(StaticMockFixture... mocks) {
+        for (StaticMockFixture mock : mocks) {
+            when(mock.setUpMockedClasses(any())).thenAnswer(
+                    invocation -> invocation.getArgument(0));
+            doNothing().when(mock).setUpMockBehaviors();
+        }
+    }
+
+    private void prepareMockBehaviours() throws Throwable {
+        when(mSessionBuilder.startMocking()).thenReturn(mSession);
+        when(mSupplyA.get()).thenReturn(mA1, mA2);
+        when(mSupplyB.get()).thenReturn(mB1, mB2);
+        prepareFixtureMocks(mA1, mA2, mB1, mB2);
+        when(mA1.setUpMockedClasses(any())).thenAnswer(invocation -> invocation.getArgument(0));
+        doNothing().when(mA1).setUpMockBehaviors();
+        when(mB1.setUpMockedClasses(any())).thenAnswer(invocation -> invocation.getArgument(0));
+        doNothing().when(mB1).setUpMockBehaviors();
+        doNothing().when(mStatement).evaluate();
+        doThrow(new AssumptionViolatedException("bad assumption, test should be skipped"))
+                .when(mSkipStatement).evaluate();
+        doThrow(new IllegalArgumentException("bad argument, test should be failed"))
+                .when(mThrowStatement).evaluate();
+        doNothing().when(mA1).tearDown();
+        doNothing().when(mB1).tearDown();
+    }
+
+    private InOrder mocksInOrder()  {
+        return inOrder(mSessionBuilder, mSession, mSupplyA, mSupplyB, mA1, mA2, mB1, mB2,
+                mStatement, mSkipStatement, mThrowStatement, mDescription);
+    }
+
+    private void verifyNoMoreImportantMockInteractions()  {
+        verifyNoMoreInteractions(mSupplyA, mSupplyB, mA1, mA2, mB1, mB2, mStatement,
+                mSkipStatement, mThrowStatement);
+    }
+
+    @Test
+    public void testRuleWorksWithExplicitFixtures() throws Throwable {
+        InOrder inOrder = mocksInOrder();
+
+        StaticMockFixtureRule rule = new StaticMockFixtureRule(mA1, mB1) {
+            @Override public StaticMockitoSessionBuilder getSessionBuilder() {
+                return mSessionBuilder;
+            }
+        };
+        Statement runMe = rule.apply(mStatement, mDescription);
+
+        inOrder.verify(mA1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mB1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mA1).setUpMockBehaviors();
+        inOrder.verify(mB1).setUpMockBehaviors();
+
+        runMe.evaluate();
+
+        inOrder.verify(mStatement).evaluate();
+        // note: tearDown in reverse order
+        inOrder.verify(mB1).tearDown();
+        inOrder.verify(mA1).tearDown();
+
+        // Round two: use the same fixtures again.
+        rule.apply(mStatement, mDescription).evaluate();
+
+        inOrder.verify(mA1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mB1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mA1).setUpMockBehaviors();
+        inOrder.verify(mB1).setUpMockBehaviors();
+        inOrder.verify(mStatement).evaluate();
+        // note: tearDown in reverse order
+        inOrder.verify(mB1).tearDown();
+        inOrder.verify(mA1).tearDown();
+
+        verifyNoMoreImportantMockInteractions();
+    }
+
+    @Test
+    public void testRuleWorksWithFixtureSuppliers() throws Throwable {
+        InOrder inOrder = mocksInOrder();
+
+        StaticMockFixtureRule rule = new StaticMockFixtureRule(mSupplyA, mSupplyB) {
+            @Override public StaticMockitoSessionBuilder getSessionBuilder() {
+                return mSessionBuilder;
+            }
+        };
+        Statement runMe = rule.apply(mStatement, mDescription);
+
+        inOrder.verify(mSupplyA).get();
+        inOrder.verify(mSupplyB).get();
+        inOrder.verify(mA1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mB1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mA1).setUpMockBehaviors();
+        inOrder.verify(mB1).setUpMockBehaviors();
+
+        runMe.evaluate();
+
+        inOrder.verify(mStatement).evaluate();
+        // note: tearDown in reverse order
+        inOrder.verify(mB1).tearDown();
+        inOrder.verify(mA1).tearDown();
+
+        // Round two: use the same suppliers again to retrieve different fixtures: mA2 and mB2
+        rule.apply(mStatement, mDescription).evaluate();
+
+        inOrder.verify(mSupplyA).get();
+        inOrder.verify(mSupplyB).get();
+        inOrder.verify(mA2).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mB2).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mA2).setUpMockBehaviors();
+        inOrder.verify(mB2).setUpMockBehaviors();
+        inOrder.verify(mStatement).evaluate();
+        // note: tearDown in reverse order
+        inOrder.verify(mB2).tearDown();
+        inOrder.verify(mA2).tearDown();
+
+        verifyNoMoreImportantMockInteractions();
+    }
+
+    @Test
+    public void testTearDownOnSkippedTests() throws Throwable {
+        InOrder inOrder = mocksInOrder();
+
+        StaticMockFixtureRule rule = new StaticMockFixtureRule(mA1, mB1) {
+            @Override public StaticMockitoSessionBuilder getSessionBuilder() {
+                return mSessionBuilder;
+            }
+        };
+        Statement skipStatement = rule.apply(mSkipStatement, mDescription);
+
+        inOrder.verify(mA1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mB1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mA1).setUpMockBehaviors();
+        inOrder.verify(mB1).setUpMockBehaviors();
+
+        try {
+            skipStatement.evaluate();
+            fail("AssumptionViolatedException should have been thrown");
+        } catch (AssumptionViolatedException e) {
+            // expected
+        }
+
+        inOrder.verify(mSkipStatement).evaluate();
+        // note: tearDown in reverse order
+        inOrder.verify(mB1).tearDown();
+        inOrder.verify(mA1).tearDown();
+
+        verifyNoMoreImportantMockInteractions();
+    }
+
+    @Test
+    public void testTearDownOnFailedTests() throws Throwable {
+        InOrder inOrder = mocksInOrder();
+
+        StaticMockFixtureRule rule = new StaticMockFixtureRule(mA1, mB1) {
+            @Override public StaticMockitoSessionBuilder getSessionBuilder() {
+                return mSessionBuilder;
+            }
+        };
+        Statement failStatement = rule.apply(mThrowStatement, mDescription);
+
+        inOrder.verify(mA1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mB1).setUpMockedClasses(any(StaticMockitoSessionBuilder.class));
+        inOrder.verify(mA1).setUpMockBehaviors();
+        inOrder.verify(mB1).setUpMockBehaviors();
+
+        try {
+            failStatement.evaluate();
+            fail("IllegalArgumentException should have been thrown");
+        } catch (IllegalArgumentException e) {
+            // expected
+        }
+
+        inOrder.verify(mThrowStatement).evaluate();
+        // note: tearDown in reverse order
+        inOrder.verify(mB1).tearDown();
+        inOrder.verify(mA1).tearDown();
+
+        verifyNoMoreImportantMockInteractions();
+    }
+}
diff --git a/javatests/com/android/modules/utils/testing/TestableDeviceConfigAndOtherStaticMocksTest.java b/javatests/com/android/modules/utils/testing/TestableDeviceConfigAndOtherStaticMocksTest.java
new file mode 100644
index 0000000..8ebe424
--- /dev/null
+++ b/javatests/com/android/modules/utils/testing/TestableDeviceConfigAndOtherStaticMocksTest.java
@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2019 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.modules.utils.testing;
+
+import android.provider.DeviceConfig;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.dx.mockito.inline.extended.ExtendedMockito;
+import com.android.dx.mockito.inline.extended.StaticMockitoSessionBuilder;
+
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class TestableDeviceConfigAndOtherStaticMocksTest {
+    @Rule
+    public StaticMockFixtureRule mStaticMockFixtureRule =
+            new StaticMockFixtureRule(TestableDeviceConfig::new, AB::new, CD::new);
+
+    private List<String> mCollected;
+
+    @Test
+    public void testDeviceConfigAndOtherStaticMocks() throws Exception {
+        mCollected = new ArrayList<>();
+        int n = 0;
+
+        String namespace = "foo";
+        String flag = "bar";
+        String flagValue = "new value";
+
+        Assert.assertNull(DeviceConfig.getProperty(namespace, flag));
+
+        A.a();
+        verifyCollected(++n, "A.a");
+
+        DeviceConfig.setProperty(namespace, flag, flagValue, false);
+
+        D.b();
+        verifyCollected(++n, "D.b");
+
+        Assert.assertEquals(flagValue, DeviceConfig.getProperty(namespace, flag));
+
+        C.b();
+        verifyCollected(++n, "C.b");
+
+        B.a();
+        verifyCollected(++n, "B.a");
+    }
+
+    private void verifyCollected(int n, String last) {
+        Assert.assertEquals(n, mCollected.size());
+        Assert.assertEquals(last, mCollected.get(n - 1));
+    }
+
+    private static class A {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    private static class B {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    private static class C {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    private static class D {
+        /* package */ static void a() {}
+        /* package */ static void b() {}
+    }
+
+    /**
+     * AB StaticMockFixture class that handles two mocked classes, {@link A} and {@link B}.
+     */
+    private class AB implements StaticMockFixture {
+        @Override
+        public StaticMockitoSessionBuilder setUpMockedClasses(
+                StaticMockitoSessionBuilder sessionBuilder) {
+            sessionBuilder.spyStatic(A.class);
+            sessionBuilder.spyStatic(B.class);
+            return sessionBuilder;
+        }
+
+        @Override
+        public void setUpMockBehaviors() {
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("A.a");
+                return null;
+            }).when(A::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("A.b");
+                return null;
+            }).when(A::b);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("B.a");
+                return null;
+            }).when(B::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("B.b");
+                return null;
+            }).when(B::b);
+        }
+
+        @Override
+        public void tearDown() {
+
+        }
+    }
+
+    /**
+     * AB StaticMockFixture class that handles two mocked classes, {@link C} and {@link D}.
+     */
+    private class CD implements StaticMockFixture {
+        @Override
+        public StaticMockitoSessionBuilder setUpMockedClasses(
+                StaticMockitoSessionBuilder sessionBuilder) {
+            sessionBuilder.spyStatic(C.class);
+            sessionBuilder.spyStatic(D.class);
+            return sessionBuilder;
+        }
+
+        @Override
+        public void setUpMockBehaviors() {
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("C.a");
+                return null;
+            }).when(C::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("C.b");
+                return null;
+            }).when(C::b);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("D.a");
+                return null;
+            }).when(D::a);
+            ExtendedMockito.doAnswer(invocation -> {
+                mCollected.add("D.b");
+                return null;
+            }).when(D::b);
+        }
+
+        @Override
+        public void tearDown() {
+
+        }
+    }
+}
diff --git a/javatests/com/android/modules/utils/testing/TestableDeviceConfigTest.java b/javatests/com/android/modules/utils/testing/TestableDeviceConfigTest.java
new file mode 100644
index 0000000..64e007e
--- /dev/null
+++ b/javatests/com/android/modules/utils/testing/TestableDeviceConfigTest.java
@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2019 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.modules.utils.testing;
+
+import static android.provider.DeviceConfig.OnPropertiesChangedListener;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.platform.test.annotations.Presubmit;
+import android.provider.DeviceConfig;
+import android.provider.DeviceConfig.Properties;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+/** Tests that ensure appropriate settings are backed up. */
+@Presubmit
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class TestableDeviceConfigTest {
+    private static final String sNamespace = "namespace1";
+    private static final String sKey = "key1";
+    private static final String sValue = "value1";
+    private static final long WAIT_FOR_PROPERTY_CHANGE_TIMEOUT_MILLIS = 2000; // 2 sec
+
+    @Rule
+    public TestableDeviceConfig.TestableDeviceConfigRule
+            mTestableDeviceConfig = new TestableDeviceConfig.TestableDeviceConfigRule();
+
+    @Test
+    public void getProperty_empty() {
+        String result = DeviceConfig.getProperty(sNamespace, sKey);
+        assertThat(result).isNull();
+    }
+
+    @Test
+    public void setAndGetProperty_sameNamespace() {
+        DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+        String result = DeviceConfig.getProperty(sNamespace, sKey);
+        assertThat(result).isEqualTo(sValue);
+    }
+
+    @Test
+    public void setAndGetProperty_differentNamespace() {
+        String newNamespace = "namespace2";
+        DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+        String result = DeviceConfig.getProperty(newNamespace, sKey);
+        assertThat(result).isNull();
+    }
+
+    @Test
+    public void setAndGetProperty_multipleNamespaces() {
+        String newNamespace = "namespace2";
+        String newValue = "value2";
+        DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+        DeviceConfig.setProperty(newNamespace, sKey, newValue, false);
+        String result = DeviceConfig.getProperty(sNamespace, sKey);
+        assertThat(result).isEqualTo(sValue);
+        result = DeviceConfig.getProperty(newNamespace, sKey);
+        assertThat(result).isEqualTo(newValue);
+    }
+
+    @Test
+    public void setAndGetProperty_overrideValue() {
+        String newValue = "value2";
+        DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+        DeviceConfig.setProperty(sNamespace, sKey, newValue, false);
+        String result = DeviceConfig.getProperty(sNamespace, sKey);
+        assertThat(result).isEqualTo(newValue);
+    }
+
+    @Test
+    public void getProperties_empty() {
+        String newKey = "key2";
+        String newValue = "value2";
+        DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+        Properties properties = DeviceConfig.getProperties(sNamespace);
+        assertThat(properties.getString(sKey, null)).isEqualTo(sValue);
+        assertThat(properties.getString(newKey, null)).isNull();
+
+        DeviceConfig.setProperty(sNamespace, newKey, newValue, false);
+        properties = DeviceConfig.getProperties(sNamespace);
+        assertThat(properties.getString(sKey, null)).isEqualTo(sValue);
+        assertThat(properties.getString(newKey, null)).isEqualTo(newValue);
+
+    }
+
+    @Test
+    public void getProperties() {
+        Properties properties = DeviceConfig.getProperties(sNamespace, sKey);
+        assertThat(properties.getString(sKey, null)).isNull();
+
+        DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+        properties = DeviceConfig.getProperties(sNamespace, sKey);
+        assertThat(properties.getString(sKey, null)).isEqualTo(sValue);
+
+        String newKey = "key2";
+        String newValue = "value2";
+        DeviceConfig.setProperty(sNamespace, newKey, newValue, false);
+        properties = DeviceConfig.getProperties(sNamespace, sKey, newKey);
+        assertThat(properties.getString(sKey, null)).isEqualTo(sValue);
+        assertThat(properties.getString(newKey, null)).isEqualTo(newValue);
+
+        String unsetKey = "key3";
+        properties = DeviceConfig.getProperties(sNamespace, newKey, unsetKey);
+        assertThat(properties.getKeyset()).containsExactly(newKey, unsetKey);
+        assertThat(properties.getString(newKey, null)).isEqualTo(newValue);
+        assertThat(properties.getString(unsetKey, null)).isNull();
+    }
+
+    @Test
+    public void testListener() throws InterruptedException {
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+
+        OnPropertiesChangedListener changeListener = (properties) -> {
+            assertThat(properties.getNamespace()).isEqualTo(sNamespace);
+            assertThat(properties.getKeyset().size()).isEqualTo(1);
+            assertThat(properties.getKeyset()).contains(sKey);
+            assertThat(properties.getString(sKey, "bogus_value")).isEqualTo(sValue);
+            assertThat(properties.getString("bogus_key", "bogus_value")).isEqualTo("bogus_value");
+            countDownLatch.countDown();
+        };
+        try {
+            DeviceConfig.addOnPropertiesChangedListener(sNamespace,
+                    ApplicationProvider.getApplicationContext().getMainExecutor(), changeListener);
+            DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+            assertThat(countDownLatch.await(
+                    WAIT_FOR_PROPERTY_CHANGE_TIMEOUT_MILLIS, TimeUnit.MILLISECONDS)).isTrue();
+        } finally {
+            DeviceConfig.removeOnPropertiesChangedListener(changeListener);
+        }
+    }
+
+}
+
+