How to specify classpath ordering in Gradle - unit-testing

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);
}
}

Answer 2

This might work:
configurations { robo }
dependencies {
robo ...
testRuntime ...
}
sourceSets.test.runtimeClasspath = configurations.robo + sourceSets.test.runtimeClasspath