Instrumented tests failure with AndroidJUnitRunner 1.0.0 and AssertJ

Instrumented Tests Failure with AndroidJUnitRunner 1.0.0 and AssertJ

This article explores a common issue encountered when using AndroidJUnitRunner 1.0.0 with AssertJ in instrumented tests: unexpected test failures. We’ll delve into the reasons behind this problem and offer solutions for ensuring smooth and reliable testing.

Understanding the Issue

JUnitRunner 1.0.0, commonly used for Android instrumentation testing, has been known to cause unexpected test failures when used with AssertJ. AssertJ, a popular assertion library, provides a fluent and expressive way to write test assertions, but its interactions with JUnitRunner 1.0.0 can lead to inconsistencies.

Possible Causes

• JUnitRunner Version Incompatibility: JUnitRunner 1.0.0 might not fully support the latest features or syntax of AssertJ, leading to misinterpretations or errors during assertion evaluation.
• Classpath Conflicts: Conflicts within the project’s classpath, where different versions of libraries are present, could interfere with the proper functioning of AssertJ or JUnitRunner.
• Missing Dependencies: Ensure you have all necessary dependencies for AssertJ and AndroidJUnitRunner properly configured in your project’s build file.

Troubleshooting and Solutions

1. Upgrade AndroidJUnitRunner

The most effective solution is to upgrade to a newer version of AndroidJUnitRunner. Version 1.1.0 and above generally provide better compatibility with AssertJ and have addressed known issues.

Updating Gradle Dependencies:

dependencies {
    androidTestImplementation("androidx.test.ext:junit:1.1.3")
    androidTestImplementation("androidx.test.runner:runner:1.4.0")
}

2. Check Classpath Conflicts

Examine your project’s dependencies to rule out any conflicts between AssertJ and other libraries.

Using Dependency Management Tools:

Tools like Gradle can help identify potential conflicts. Use the “dependencies” task to analyze your project’s dependency tree.

./gradlew dependencies

3. Verify Dependencies

Confirm that you have the correct AssertJ dependency included in your test project:

Adding AssertJ Dependency:

dependencies {
    androidTestImplementation("org.assertj:assertj-core:3.23.1")
}

4. Consider Using Alternative Assertions

If the above solutions don’t resolve the issue, consider using alternative assertion libraries such as Hamcrest or Truth.

Hamcrest Example:

import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.is;
import static org.junit.Assert.assertThat;

assertThat(actualValue, is(equalTo(expectedValue)));

Example: Assertion Failure

Here’s an example of a typical test failure with AndroidJUnitRunner 1.0.0 and AssertJ:

Test Code:

import org.junit.Test;
import org.junit.runner.RunWith;
import androidx.test.ext.junit.runners.AndroidJUnit4;
import static org.assertj.core.api.Assertions.assertThat;

@RunWith(AndroidJUnit4.class)
public class ExampleInstrumentedTest {
    @Test
    public void testAssertJ() {
        String actual = "Hello";
        String expected = "Hello";
        assertThat(actual).isEqualTo(expected);
    }
}

Output:

FAILURE: Test failed to run to completion.
There were errors during the test run. 
See the console for more details. 

Conclusion

Understanding the causes of test failures with AndroidJUnitRunner 1.0.0 and AssertJ allows for effective troubleshooting and ensures reliable testing. Upgrading to a newer AndroidJUnitRunner version, verifying dependencies, and considering alternative assertion libraries can provide the necessary solutions for a stable testing environment.