Truth Android

A set of Truth assertions geared toward testing Android.

Writing tests is not the most glamorous part of developing an Android application but it is an invaluable one. Using libraries like JUnit and Truth provide a great starting point for writing tests.

This library is an extension of Truth which aims to make it even easier to test Android.

Truth Android
assertThat(view).isGone();
Regular JUnit
assertEquals(View.GONE, view.getVisibility());
Regular Truth
assertThat(view.getVisibility()).isEqualTo(View.GONE);

When failing, the Truth Android assertion produces an output which allows you to immediately recognize the problem: Expected visibility <gone> but was <invisible>.

Compare that to the output of regular Truth expected:<[8]> but was:<[4]> and regular JUnit expected: <8> but was: <4> and you should immediately see the advantage.

Because Truth Android offers assertions directly on objects rather than properties they can be chained together.

Truth Android
assertThat(layout).isVisible()
    .isVertical()
    .hasChildCount(4)
    .hasShowDividers(SHOW_DIVIDERS_MIDDLE);
Regular JUnit
assertEquals(View.VISIBLE, layout.getVisibility());
assertEquals(VERTICAL, layout.getOrientation());
assertEquals(4, layout.getChildCount());
assertEquals(SHOW_DIVIDERS_MIDDLE, layout.getShowDividers());
Regular Truth
assertThat(layout.getVisibility()).isEqualTo(View.VISIBLE);
assertThat(layout.getOrientation()).isEqualTo(VERTICAL);
assertThat(layout.getChildCount()).isEqualTo(4);
assertThat(layout.getShowDividers()).isEqualTo(SHOW_DIVIDERS_MIDDLE);

Assertions exist for nearly every object that you would ever want to test, from LinearLayout to ActionBar to Fragment to MenuItem. Everything in the support library is included too.

To get started writing tests add the following import:

import static com.pkware.truth.android.Assertions.assertThat;
Add-On Modules

Modules are also provided for the add-on Android libraries. Add the dependency (listed below) and use the following imports:

  • support-v4

    import static com.pkware.truth.android.support.v4.Assertions.assertThat;
  • Google Play Services

    import static com.pkware.truth.android.playservices.Assertions.assertThat;
  • appcompat-v7

    import static com.pkware.truth.android.appcompat.v7.Assertions.assertThat;
  • design

    import static com.pkware.truth.android.design.Assertions.assertThat;
  • mediarouter-v7

    import static com.pkware.truth.android.mediarouter.v7.Assertions.assertThat;
  • gridlayout-v7

    import static com.pkware.truth.android.gridlayout.v7.Assertions.assertThat;
  • cardview-v7

    import static com.pkware.truth.android.cardview.v7.Assertions.assertThat;
  • recyclerview-v7

    import static com.pkware.truth.android.recyclerview.v7.Assertions.assertThat;
  • pallete-v7

    import static com.pkware.truth.android.pallete.v7.Assertions.assertThat;
Extending

The provided assertions have also been designed to be extended for any custom controls you have developed.

public class CustomLayout extends LinearLayout {
  public int getBehavior() {
    /* ... */
  }
}

Use the following pattern to set up your assertions.

public final class CustomLayoutSubject extends AbstractLinearLayoutSubject<CustomLayoutSubject, CustomLayout> {
  private static final SubjectFactory<CustomLayoutSubject, CustomLayout> CUSTOM_LAYOUT_SUBJECT_FACTORY =
      new SubjectFactory<CustomLayoutSubject, CustomLayout>() {
        @Override
        public CustomLayoutSubject getSubject(FailureStrategy failureStrategy, @Nullable CustomLayout target) {
          return new CustomLayoutSubject(failureStrategy, target);
        }
      };

  public static CustomLayoutSubject assertThat(@Nullable CustomLayout actual) {
    return assertAbout(CUSTOM_LAYOUT_SUBJECT_FACTORY).that(actual);
  }

  private CustomLayoutSubject(FailureStrategy failureStrategy, CustomLayout subject) {
    super(failureStrategy, subject);
  }

  public CustomLayoutSubject hasSomeBehavior() {
    assertThat(actual.getBehavior())
        .withFailureMessage("Expected some behavior but was doing other behavior.")
        .isEqualTo(42)
    return this;
  }
}

Now static import CustomLayoutSubject.assertThat in your test classes.

For more information about writing custom assertions see the official documentation.

Download
  • Android module:

    androidTestCompile 'com.pkware.truth-android:truth-android:1.0.0'
  • support-v4 module:

    androidTestCompile 'com.pkware.truth-android:truth-android-support-v4:1.0.0'
  • Google Play Services module:

    androidTestCompile 'com.pkware.truth-android:truth-android-play-services:1.0.0'
  • Design library module:

    androidTestCompile 'com.pkware.truth-android:truth-android-pallete-v7:1.0.0'
  • appcompat-v7 module:

    androidTestCompile 'com.pkware.truth-android:truth-android-appcompat-v7:1.0.0'
  • mediarouter-v7 module:

    androidTestCompile 'com.pkware.truth-android:truth-android-mediarouter-v7:1.0.0'
  • gridlayout-v7 module:

    androidTestCompile 'com.pkware.truth-android:truth-android-gridlayout-v7:1.0.0'
  • cardview-v7 module:

    androidTestCompile 'com.pkware.truth-android:truth-android-cardview-v7:1.0.0'
  • recyclerview-v7 module:

    androidTestCompile 'com.pkware.truth-android:truth-android-recyclerview-v7:1.0.0'
  • pallete-v7 module:

    androidTestCompile 'com.pkware.truth-android:truth-android-pallete-v7:1.0.0'
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