LeakCanary + Robolectricでテストするときの注意 ref: http://qiita.com/wakwak3125/items/1cae809dbfa6e68b5890

build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "com.wakwak.leakcanarytest"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {

        beta {
            minifyEnabled false
        }

        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    testCompile 'org.robolectric:robolectric:3.0'

    compile 'com.android.support:appcompat-v7:23.1.1'

    betaCompile 'com.squareup.leakcanary:leakcanary-android:1.4-beta1'
    releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.4-beta1'
}

ExampleUnitTest

@RunWith(RobolectricGradleTestRunner.class)
@Config(constants = BuildConfig.class, sdk = 21, packageName = "com.wakwak.leakcanarytest")
public class ExampleUnitTest {
    @Test
    public void addition_isCorrect() throws Exception {
        assertEquals(4, 2 + 2);
    }
}

file0.txt

betaCompile 'com.squareup.leakcanary:leakcanary-android:1.4-beta1'
releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.4-beta1'

file4.txt

./gradlew testReleaseUnitTest                                                

:app:preBuild UP-TO-DATE
:app:preReleaseBuild UP-TO-DATE
:app:checkReleaseManifest
:app:preBetaBuild UP-TO-DATE
:app:preDebugBuild UP-TO-DATE
:app:prepareComAndroidSupportAppcompatV72311Library UP-TO-DATE
:app:prepareComAndroidSupportSupportV42311Library UP-TO-DATE
:app:prepareComSquareupLeakcanaryLeakcanaryAndroidNoOp14Beta1Library UP-TO-DATE
:app:prepareReleaseDependencies
:app:compileReleaseAidl UP-TO-DATE
:app:compileReleaseRenderscript UP-TO-DATE
:app:generateReleaseBuildConfig UP-TO-DATE
:app:generateReleaseAssets UP-TO-DATE
:app:mergeReleaseAssets UP-TO-DATE
:app:generateReleaseResValues UP-TO-DATE
:app:generateReleaseResources UP-TO-DATE
:app:mergeReleaseResources UP-TO-DATE
:app:processReleaseManifest
:app:processReleaseResources
:app:generateReleaseSources
:app:processReleaseJavaRes UP-TO-DATE
:app:compileReleaseJavaWithJavac
:app:preReleaseUnitTestBuild UP-TO-DATE
:app:prepareReleaseUnitTestDependencies
:app:processReleaseUnitTestJavaRes UP-TO-DATE
:app:compileReleaseUnitTestJavaWithJavac
:app:compileReleaseUnitTestSources
:app:mockableAndroidJar UP-TO-DATE
:app:assembleReleaseUnitTest
:app:testReleaseUnitTest

BUILD SUCCESSFUL

Total time: 13.652 secs

file5.txt

./gradlew testBetaUnitTest

:app:preBuild UP-TO-DATE
:app:preBetaBuild UP-TO-DATE
:app:checkBetaManifest
:app:preDebugBuild UP-TO-DATE
:app:preReleaseBuild UP-TO-DATE
:app:prepareComAndroidSupportAppcompatV72311Library UP-TO-DATE
:app:prepareComAndroidSupportSupportV42311Library UP-TO-DATE
:app:prepareComSquareupLeakcanaryLeakcanaryAndroid14Beta1Library UP-TO-DATE
:app:prepareBetaDependencies
:app:compileBetaAidl UP-TO-DATE
:app:compileBetaRenderscript UP-TO-DATE
:app:generateBetaBuildConfig UP-TO-DATE
:app:generateBetaAssets UP-TO-DATE
:app:mergeBetaAssets UP-TO-DATE
:app:generateBetaResValues UP-TO-DATE
:app:generateBetaResources UP-TO-DATE
:app:mergeBetaResources UP-TO-DATE
:app:processBetaManifest UP-TO-DATE
:app:processBetaResources UP-TO-DATE
:app:generateBetaSources UP-TO-DATE
:app:processBetaJavaRes UP-TO-DATE
:app:compileBetaJavaWithJavac UP-TO-DATE
:app:preBetaUnitTestBuild UP-TO-DATE
:app:prepareBetaUnitTestDependencies
:app:processBetaUnitTestJavaRes UP-TO-DATE
:app:compileBetaUnitTestJavaWithJavac UP-TO-DATE
:app:compileBetaUnitTestSources UP-TO-DATE
:app:mockableAndroidJar UP-TO-DATE
:app:assembleBetaUnitTest UP-TO-DATE
:app:testBetaUnitTest

com.wakwak.leakcanarytest.ExampleUnitTest > addition_isCorrect FAILED
    java.lang.RuntimeException
        Caused by: java.lang.NullPointerException

1 test completed, 1 failed
:app:testBetaUnitTest FAILED

FAILURE: Build failed with an exception.

MyApplication

public class MyApplication extends Application {

    @Override
    public void onCreate() {
        super.onCreate();
        try {
            LeakCanary.install(this);
        } catch (Exception ignore) {

        }
    }
}