Dagger not generating components for /test class

Question

I am following the guide here: https://github.com/ecgreb/dagger-2-testing-demo

I have the following setup in my app/src/main (the injection and @Provides code omitte

Answer 1

For Android Studio 3 and dagger 2.13 the already mentioned annotation processors are needed:

testAnnotationProcessor 'com.google.dagger:dagger-compiler:2.13'

But also do not forgot to do this for the instrumented test under androidTest:

androidTestAnnotationProcessor'com.google.dagger:dagger-compiler:2.13'

You might get the impression that this alone does not work, because the DaggerXYZ classes are not generated. After hours I found out that the test source generation is only triggered when the tests are executed. If you start a test or androidTest from Android Studio the source generation should be triggered.

If you need this earlier trigger gradle manually:

gradlew <moduledirectory>:compile<Flavor>DebugAndroidTestSources
gradlew <moduledirectory>:compile<Flavor>DebugTestSources

Replace Debug if you run a test in a different build type.

Note:

If you are using multiDexEnable = true you might get an error:

Test running failed: Instrumentation run failed due to 'java.lang.IncompatibleClassChangeError'

Use a different runner in this case:

android {

  defaultConfig {
    multiDexEnabled true
    testInstrumentationRunner "com.android.test.runner.MultiDexTestRunner"

Answer 2

I ran ./gradlew build from the command line and got information about a missing Provides method that Android Studio was not telling me about.