What would run ExampleUnitTest but not find ExampleInstrumentedTest?

Question

Android Studio: 3.6.1 Gradle: gradle-5.6.4-all

I am ready to test my app and found that Android Studio produces example unit and instrumented tests. So, I right-click ExampleUnitTest, select Run and it runs just fine. However, when I do this for ExampleInstrumentedTest, it fails with the following error message:

Process finished with exit code 1 Class not found: "com.example.jbiss.petminder.ExampleInstrumentedTest"

However, ExampleInstrumentedTest is located in the default androidTest path (...\app\src\androidTest\java\com\example\jbiss\petminder) and ExampleUnitTest is located in the default test path (...\app\src\test\java\com\example\jbiss\petminder).

While I altered the auto-generated Android Studio source to start experimenting with test coding, that should have nothing to do with the Class not found: "com.example.jbiss.petminder.ExampleInstrumentedTest" error. Here is my altered code (using the auto-generated ExampleInstrumentedTest code as the baseline):

package com.example.jbiss.petminder;

import android.content.Context;

import com.example.jbiss.petminder.activities.MainActivity;

import androidx.test.espresso.accessibility.AccessibilityChecks;
import androidx.test.filters.SmallTest;
import androidx.test.platform.app.InstrumentationRegistry;
import androidx.test.ext.junit.runners.AndroidJUnit4;
import androidx.test.rule.ActivityTestRule;

import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;

import static androidx.test.espresso.Espresso.onView;
import static androidx.test.espresso.action.ViewActions.click;
import static androidx.test.espresso.assertion.ViewAssertions.matches;
import static androidx.test.espresso.matcher.ViewMatchers.withContentDescription;
import static androidx.test.espresso.matcher.ViewMatchers.withId;
import static org.junit.Assert.*;

/**
* Instrumentation test, which will execute on an Android device.
*
* @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
*/
@RunWith(AndroidJUnit4.class)
@SmallTest
public class ExampleInstrumentedTest {

@Before
public void setUp(){
AccessibilityChecks.enable();
}

@Rule
public ActivityTestRule<MainActivity> mMainActivityActivityTestRule =
new ActivityTestRule<>(MainActivity.class);

@Test
public void useAppContext() throws Exception {
// Context of the app under test.
Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();

assertEquals("com.example.jbiss.petminder", appContext.getPackageName());
onView(withId(R.id.action_add_pet)).perform(click()).check(matches(withContentDescription(R.layout.activity_add_pet)));
}
}

Here is my app's build.gradle file:

apply plugin: 'com.android.application'

android {
compileSdkVersion 28
packagingOptions {
exclude 'META-INF/DEPENDENCIES'
}
buildToolsVersion '28.0.3'
defaultConfig {
applicationId "com.example.jbiss.petminder"
minSdkVersion 24
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}

compileOptions {
encoding "UTF-8"
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}

dataBinding {
enabled = true
}

// Gradle automatically adds 'android.test.runner' as a dependency.
useLibrary 'android.test.runner'

useLibrary 'android.test.base'
useLibrary 'android.test.mock'

testOptions {
unitTests.includeAndroidResources = true
}
}

dependencies {
def nav_version = "2.3.0-alpha03"

implementation "android.arch.navigation:navigation-fragment-ktx:1.0.0"
implementation "android.arch.navigation:navigation-ui-ktx:1.0.0"

// Java language implementation: navigation
implementation "androidx.navigation:navigation-fragment:$nav_version"
implementation "androidx.navigation:navigation-ui:$nav_version"

// Dynamic Feature Module Support
implementation "androidx.navigation:navigation-dynamic-features-fragment:$nav_version"

// Testing Navigation
androidTestImplementation "androidx.navigation:navigation-testing:$nav_version"

// use -ktx for Kotlin
implementation "android.arch.navigation:navigation-ui:$nav_version"

// use -ktx for Kotlin

//noinspection GradleCompatible
implementation 'com.android.support:support-v4:28.1.0'
implementation
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation 'com.android.support:appcompat-v7:28.1.0'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
implementation 'com.android.support:design:28.1.0'
implementation 'com.android.support:cardview-v7:28.1.0'
implementation 'androidx.recyclerview:recyclerview:1.1.0'
implementation 'com.google.android.material:material:1.1.0'
implementation 'com.android.support:mediarouter-v7:28.1.0'

/**
* directly from https://developer.android.com/topic/libraries/architecture/adding-components#lifecycle
*/
def lifecycle_version = "2.2.0"
def arch_version = "2.1.0"
def room_version = "2.2.4"

// ViewModel
implementation "androidx.lifecycle:lifecycle-viewmodel:$lifecycle_version"
// LiveData
implementation "androidx.lifecycle:lifecycle-livedata:$lifecycle_version"
// Lifecycles only (without ViewModel or LiveData)
implementation "androidx.lifecycle:lifecycle-runtime:$lifecycle_version"

// Saved state module for ViewModel
implementation "androidx.lifecycle:lifecycle-viewmodel-savedstate:$lifecycle_version"

// Annotation processor
annotationProcessor "androidx.lifecycle:lifecycle-compiler:$lifecycle_version"
// alternately - if using Java8, use the following instead of lifecycle-compiler
implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"

// optional - helpers for implementing LifecycleOwner in a Service
implementation "androidx.lifecycle:lifecycle-service:$lifecycle_version"

// optional - ProcessLifecycleOwner provides a lifecycle for the whole application process
implementation "androidx.lifecycle:lifecycle-process:$lifecycle_version"

// optional - ReactiveStreams support for LiveData
implementation "androidx.lifecycle:lifecycle-reactivestreams:$lifecycle_version"

// optional - Test helpers for LiveData
testImplementation "androidx.arch.core:core-testing:$arch_version"

implementation "androidx.lifecycle:lifecycle-reactivestreams:$lifecycle_version"

// optional - Test helpers for LiveData
testImplementation "androidx.arch.core:core-testing:$arch_version"
implementation "androidx.room:room-runtime:$room_version"
annotationProcessor "androidx.room:room-compiler:$room_version"

// use kapt for Kotlin

// optional - RxJava support for Room

//implementation "androidx.room:room-rxjava2:$room_version"

// optional - Guava support for Room, including Optional and ListenableFuture

//implementation "androidx.room:room-guava:$room_version"

// Test helpers
testImplementation "androidx.room:room-testing:$room_version"
testImplementation 'org.testng:testng:6.9.10'

// Required -- JUnit 4 framework
testImplementation 'junit:junit:4.12'
// Optional -- Robolectric environment
testImplementation 'androidx.test:core:1.2.0'
// Optional -- Mockito framework
testImplementation 'org.mockito:mockito-core:2.19.0'
implementation 'androidx.appcompat:appcompat:1.1.0'

implementation 'com.google.api-client:google-api-client:1.30.2'

// Core library
androidTestImplementation 'androidx.test:core:1.2.0'

// AndroidJUnitRunner and JUnit Rules
androidTestImplementation 'androidx.test:runner:1.2.0'
androidTestImplementation 'androidx.test:rules:1.2.0'

// Assertions
androidTestImplementation 'androidx.test.ext:junit:1.1.1'
androidTestImplementation 'androidx.test.ext:truth:1.2.0'
androidTestImplementation 'com.google.truth:truth:0.42'

// Espresso dependencies
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
androidTestImplementation 'androidx.test.espresso:espresso-contrib:3.2.0'
androidTestImplementation 'androidx.test.espresso:espresso-intents:3.2.0'
androidTestImplementation 'androidx.test.espresso:espresso-accessibility:3.2.0'
androidTestImplementation 'androidx.test.espresso:espresso-web:3.2.0'
androidTestImplementation 'androidx.test.espresso.idling:idling-concurrent:3.2.0'

// The following Espresso dependency can be either "implementation"
// or "androidTestImplementation", depending on whether you want the
// dependency to appear on your APK's compile classpath or the test APK
// classpath.
androidTestImplementation 'androidx.test.espresso:espresso-idling-resource:3.2.0'
// debugImplementation because LeakCanary should only run in debug builds.
debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.2'
// Optional -- Hamcrest library
androidTestImplementation 'org.hamcrest:hamcrest-library:1.3'
// Optional -- UI testing with UI Automator
androidTestImplementation 'androidx.test.uiautomator:uiautomator:2.2.0'

}

configurations.all {
resolutionStrategy.eachDependency { DependencyResolveDetails details ->
def requested = details.requested
if (requested.group == 'com.android.support') {
//if (requested.group == "androidx") {
if (!requested.name.startsWith("multidex")) {
details.useVersion '25.3.1'
}
}
}
}

While I might have other problems in my code, what would cause this failure to find an existing ExampleInstrumentedTest file with public class ExampleInstrumentedTest{} explicitly stated in that file?

The code seems to be formated as shown in Build instrumented unit tests

The following provided no answer:

• public class ExampleInstrumentedTest

• No tests were found - testNG, IntelliJ [duplicate]

• “No tests were found” during Android UI Testing

• No test were found

Answer 1

There's a mixing between androidx.test and android.support.test/android.test which is not advised. Changing the testInstrumentationRunner to the below could resolve the problem:

testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

Here's a sample you could refer to for using androidx.test as the main testing framework.