How to specify classpath ordering in Gradle

Question

I need to control the ordering of jars in the testRuntime configuration.

I must make sure that robolectric-x.x.jar comes before android.jar, or else I get the dreaded RuntimeException("Stub!").

How do I do that?

Answer 1

Here is my complete build.gradle for running Robolectric tests against my Android app, which uses RoboGuice:

apply plugin: 'java'

androidJar = new File(System.getenv('ANDROID_HOME'), '/platforms/android-7/android.jar')

configurations { robo }

dependencies {
    robo('com.pivotallabs:robolectric:1.0-RC1')
    testCompile('org.roboguice:roboguice:1.1.2')
    testCompile('junit:junit:4.8.2')
    testCompile project (':app')
    testCompile files(androidJar)
}

sourceSets.test.compileClasspath = configurations.robo + sourceSets.test.compileClasspath
sourceSets.test.runtimeClasspath = configurations.robo + sourceSets.test.runtimeClasspath

test {
    excludes = ['**/MyRobolectricTestRunner.class']
}

I had to add an exclusion for the test runner, or else Gradle will throw an exception.

MyRobolectricTestRunner.java looks like this:

package com.acme.myapp;

import java.io.File;
import org.junit.runners.model.InitializationError;
import roboguice.application.RoboApplication;
import roboguice.inject.ContextScope;
import com.google.inject.Injector;
import com.xtremelabs.robolectric.Robolectric;
import com.xtremelabs.robolectric.RobolectricTestRunner;

public class MyRobolectricTestRunner extends RobolectricTestRunner {
    public MyRobolectricTestRunner(Class<?> testClass) throws InitializationError {
        // Tell Robolectric where to find AndroidManifest.xml and res/
        super(testClass, new File("../app"));
    }

    /**
     * Enable injection into tests as well...
     */
    @Override
    public void prepareTest(Object test) {
        RoboApplication myApplication = (RoboApplication) Robolectric.application;
        Injector injector = myApplication.getInjector();
        ContextScope contextScope = injector.getInstance(ContextScope.class);
        contextScope.enter(myApplication);
        injector.injectMembers(test);
    }

}

And here's a sample test that illustrates injection:

package com.acme.myapp;

import static org.junit.Assert.assertEquals;

import org.junit.Test;
import org.junit.runner.RunWith;
import roboguice.inject.InjectResource;

@RunWith(MyRobolectricTestRunner.class)
public class StringFormattingTest {

    @InjectResource(R.string.info_pending_amount)
    private String pendingAmountPattern;

    @Test
    public void testFormatInfoPendingAmount() {
        String s = String.format(pendingAmountPattern, 20.0d, "EUR");
        assertEquals("Only a part of your stake (20,00 EUR) was accepted", s);
    }

}