Bug 1222120 - Part 1: Add custom Robolectric test runner. r=vivek

This exports the buildDir to Robolectric via an Android-Gradle
buildConfigField, and then lightly massages the existing test runner
to use the exported value.

--HG--
extra : commitid : FKCOBaaJbdn
extra : rebase_source : b47d77c74b6d5179145c9539503a27630a3aa40c

mobile/android/base/build.gradle

@@ -9,6 +9,8 @@ android {
     defaultConfig {
         targetSdkVersion 22
         minSdkVersion 9
+        // Used by Robolectric based tests; see TestRunner.
+        buildConfigField 'String', 'BUILD_DIR', "\"${project.buildDir}\""
     }
 
     compileOptions {

mobile/android/gradle/base/build.gradle

@@ -7,6 +7,8 @@ android {
     defaultConfig {
         targetSdkVersion 22
         minSdkVersion 9
+        // Used by Robolectric based tests; see TestRunner.
+        buildConfigField 'String', 'BUILD_DIR', "\"${project.buildDir}\""
     }
 
     compileOptions {

mobile/android/tests/background/junit4/src/org/mozilla/gecko/background/testhelpers/TestRunner.java

@@ -0,0 +1,138 @@
+/**
+ * The MIT License
+ * 
+ * Copyright (c) 2010 Xtreme Labs and Pivotal Labs
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package org.mozilla.gecko.background.testhelpers;
+
+import org.junit.runners.model.InitializationError;
+import org.robolectric.RobolectricGradleTestRunner;
+import org.robolectric.annotation.Config;
+import org.robolectric.manifest.AndroidManifest;
+import org.robolectric.res.FileFsFile;
+import org.robolectric.res.FsFile;
+import org.robolectric.util.Logger;
+import org.robolectric.util.ReflectionHelpers;
+
+/**
+ * Test runner customized for running unit tests either through the Gradle CLI or
+ * Android Studio. The runner uses the build type and build flavor to compute the
+ * resource, asset, and AndroidManifest paths.
+ *
+ * This test runner requires that you set the 'constants' field on the @Config
+ * annotation (or the org.robolectric.Config.properties file) for your tests.
+ *
+ * This is a modified version of
+ * https://github.com/robolectric/robolectric/blob/8676da2daa4c140679fb5903696b8191415cec8f/robolectric/src/main/java/org/robolectric/RobolectricGradleTestRunner.java
+ * that uses a Gradle `buildConfigField` to find build outputs.
+ * See https://github.com/robolectric/robolectric/issues/1648#issuecomment-113731011.
+ */
+public class TestRunner extends RobolectricGradleTestRunner {
+    private FsFile buildFolder;
+
+    public TestRunner(Class<?> klass) throws InitializationError {
+        super(klass);
+    }
+
+    @Override
+    protected AndroidManifest getAppManifest(Config config) {
+        if (config.constants() == Void.class) {
+            Logger.error("Field 'constants' not specified in @Config annotation");
+            Logger.error("This is required when using RobolectricGradleTestRunner!");
+            throw new RuntimeException("No 'constants' field in @Config annotation!");
+        }
+
+        buildFolder = FileFsFile.from(getBuildDir(config)).join("intermediates");
+
+        final String type = getType(config);
+        final String flavor = getFlavor(config);
+        final String packageName = getPackageName(config);
+
+        final FsFile res;
+        final FsFile assets;
+        final FsFile manifest;
+
+        if (areResourcesFromLibrary()) {
+            FsFile bundlesFolder = buildFolder.join("bundles", flavor, type);
+            res = bundlesFolder.join("res");
+            assets = bundlesFolder.join("assets");
+            manifest = bundlesFolder.join("AndroidManifest.xml");
+        } else {
+            if (buildFolder.join("res", "merged").exists()) {
+                res = buildFolder.join("res", "merged", flavor, type);
+            } else if(buildFolder.join("res").exists()) {
+                res = buildFolder.join("res", flavor, type);
+            } else {
+                throw new IllegalStateException("No resource folder found");
+            }
+            assets = buildFolder.join("assets", flavor, type);
+            manifest = buildFolder.join("manifests", "full", flavor, type, "AndroidManifest.xml");
+        }
+
+        Logger.debug("Robolectric assets directory: " + assets.getPath());
+        Logger.debug("   Robolectric res directory: " + res.getPath());
+        Logger.debug("   Robolectric manifest path: " + manifest.getPath());
+        Logger.debug("    Robolectric package name: " + packageName);
+        return new AndroidManifest(manifest, res, assets, packageName);
+    }
+
+    private boolean areResourcesFromLibrary() {
+        return buildFolder.join("bundles").exists();
+    }
+
+    private static String getType(Config config) {
+        try {
+            return ReflectionHelpers.getStaticField(config.constants(), "BUILD_TYPE");
+        } catch (Throwable e) {
+            return null;
+        }
+    }
+
+    private static String getFlavor(Config config) {
+        try {
+            return ReflectionHelpers.getStaticField(config.constants(), "FLAVOR");
+        } catch (Throwable e) {
+            return null;
+        }
+    }
+
+    private static String getPackageName(Config config) {
+        try {
+            final String packageName = config.packageName();
+            if (packageName != null && !packageName.isEmpty()) {
+                return packageName;
+            } else {
+                return ReflectionHelpers.getStaticField(config.constants(), "APPLICATION_ID");
+            }
+        } catch (Throwable e) {
+            return null;
+        }
+    }
+
+    private String getBuildDir(Config config) {
+        try {
+            return ReflectionHelpers.getStaticField(config.constants(), "BUILD_DIR");
+        } catch (Throwable e) {
+            return null;
+        }
+    }
+}