Add utility class to temporarily elevate adb root.

Test: Unit tests
Bug: 159843590
Change-Id: Ie96a40ba8c47deef601cf73ddea786d4dbf0516c
Merged-In: Ie96a40ba8c47deef601cf73ddea786d4dbf0516c

3 files changed, 153 insertions, 0 deletions

diff --git a/src/com/android/tradefed/util/AdbRootElevator.java b/src/com/android/tradefed/util/AdbRootElevator.java
new file mode 100644
index 000000000..fa6eb0cea
--- /dev/null
+++ b/src/com/android/tradefed/util/AdbRootElevator.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2020 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.tradefed.util;
+
+import com.android.tradefed.device.DeviceNotAvailableException;
+import com.android.tradefed.device.INativeDevice;
+
+/**
+ * An {@link java.lang.AutoCloseable} that enables adb root when constructed if needed and restores
+ * root state when complete.
+ */
+public class AdbRootElevator implements AutoCloseable {
+    private final boolean mWasRoot;
+    private final INativeDevice mDevice;
+
+    public AdbRootElevator(INativeDevice device) throws DeviceNotAvailableException {
+        mDevice = device;
+        mWasRoot = mDevice.isAdbRoot();
+        if (!mWasRoot) {
+            if (!mDevice.enableAdbRoot()) {
+                throw new RuntimeException("Failed to enable adb root.");
+            }
+        }
+    }
+
+    @Override
+    public void close() {
+        if (!mWasRoot) {
+            try {
+                mDevice.disableAdbRoot();
+            } catch (DeviceNotAvailableException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+}
diff --git a/tests/src/com/android/tradefed/UnitTests.java b/tests/src/com/android/tradefed/UnitTests.java
index b9ec8821e..60bc4bfb6 100644
--- a/tests/src/com/android/tradefed/UnitTests.java
+++ b/tests/src/com/android/tradefed/UnitTests.java
@@ -335,6 +335,7 @@ import com.android.tradefed.testtype.suite.retry.RetryReschedulerTest;
 import com.android.tradefed.util.AaptParserTest;
 import com.android.tradefed.util.AbiFormatterTest;
 import com.android.tradefed.util.AbiUtilsTest;
+import com.android.tradefed.util.AdbRootElevatorTest;
 import com.android.tradefed.util.AppVersionFetcherTest;
 import com.android.tradefed.util.ArrayUtilTest;
 import com.android.tradefed.util.BluetoothUtilsTest;
@@ -848,6 +849,7 @@ import org.junit.runners.Suite.SuiteClasses;
     AaptParserTest.class,
     AbiFormatterTest.class,
     AbiUtilsTest.class,
+    AdbRootElevatorTest.class,
     AppVersionFetcherTest.class,
     ArrayUtilTest.class,
     BluetoothUtilsTest.class,
diff --git a/tests/src/com/android/tradefed/util/AdbRootElevatorTest.java b/tests/src/com/android/tradefed/util/AdbRootElevatorTest.java
new file mode 100644
index 000000000..2e808d341
--- /dev/null
+++ b/tests/src/com/android/tradefed/util/AdbRootElevatorTest.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2020 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.tradefed.util;
+
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.verify;
+
+import com.android.tradefed.device.DeviceNotAvailableException;
+import com.android.tradefed.device.INativeDevice;
+
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+
+/** Unit tests for {@link AdbRootElevator}. */
+@RunWith(JUnit4.class)
+public class AdbRootElevatorTest {
+    @Mock INativeDevice mMockDevice;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+    }
+
+    @Test
+    public void testEnablesAndDisablesRoot() throws Exception {
+        when(mMockDevice.isAdbRoot()).thenReturn(false);
+        when(mMockDevice.enableAdbRoot()).thenReturn(true);
+
+        try (AdbRootElevator adbRoot = new AdbRootElevator(mMockDevice)) {
+            mMockDevice.waitForDeviceAvailable();
+        }
+
+        InOrder inOrder = Mockito.inOrder(mMockDevice);
+        inOrder.verify(mMockDevice).isAdbRoot();
+        inOrder.verify(mMockDevice).enableAdbRoot();
+        inOrder.verify(mMockDevice).waitForDeviceAvailable();
+        inOrder.verify(mMockDevice).disableAdbRoot();
+    }
+
+    @Test
+    public void testRootAlreadyEnabled_doesNotEnableOrDisableRoot() throws Exception {
+        when(mMockDevice.isAdbRoot()).thenReturn(true);
+
+        try (AdbRootElevator adbRoot = new AdbRootElevator(mMockDevice)) {
+            mMockDevice.waitForDeviceAvailable();
+        }
+
+        InOrder inOrder = Mockito.inOrder(mMockDevice);
+        inOrder.verify(mMockDevice).isAdbRoot();
+        inOrder.verify(mMockDevice).waitForDeviceAvailable();
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testFailsToEnableAdbRoot_throwsException() throws Exception {
+        when(mMockDevice.isAdbRoot()).thenReturn(false);
+        when(mMockDevice.enableAdbRoot()).thenReturn(false);
+
+        try (AdbRootElevator adbRoot = new AdbRootElevator(mMockDevice)) {
+            fail("Exception should have already been thrown.");
+        } catch (Exception e) {
+            // Expected.
+        }
+
+        verify(mMockDevice, never()).disableAdbRoot();
+    }
+
+    @Test
+    public void testDeviceNotAvailableOnRoot_throwsException() throws Exception {
+        when(mMockDevice.isAdbRoot()).thenReturn(false);
+        when(mMockDevice.enableAdbRoot()).thenThrow(new DeviceNotAvailableException());
+
+        try (AdbRootElevator adbRoot = new AdbRootElevator(mMockDevice)) {
+            fail("Exception should have already been thrown.");
+        } catch (DeviceNotAvailableException e) {
+            // Expected.
+        }
+
+        verify(mMockDevice, never()).disableAdbRoot();
+    }
+}