Issues using custom testInstrumentationRunner-CodePudding

I've not found any post on Stack Overflow that helped, so I'm posting my own question.

I have a custom testInstrumentationRunner that when set doesn't run any tests. The logs says:

App restart successful without requiring a re-install.
Running tests
adb shell am instrument -w -m  --no-window-animation  -e debug false -e class 'com.my.app.MyFragmentTest' com.my.app.debug.test/com.my.app.CustomTestRunner
Connected to process on device

When running the normal androidx.test.runner.AndroidJUnitRunner the tests run, but fail, because I need the custom runner.

The runner is set up like the androidx one, in:

defaultConfig {
// testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner
   testInstrumentationRunner "com.my.app.CustomTestRunner"
}

It's also located in the com.my.app package in androidTest-folder

The code for the runner is:

package com.my.app

import ...

class CustomTestRunner: AndroidJUnitRunner() {
    override fun newApplication(cl: ClassLoader?, className: String?, context: Context?): Application {
        DexOpener.install(this)
        Timber.i("This should print hopefully")
        return super.newApplication(cl, ApplicationTest::class.java.canonicalName, context)
    }
}

Not sure if it matters, but here's the code for the application class, which extends the application class used for the app itself:

package com.my.app

class ApplicationTest: MyApplication() {
    override fun onCreate() {
        super.onCreate()
        appContext = applicationContext
        initializeDependencyInjection()
    }

    override fun initializeDependencyInjection() {}
}

I have a test-case I'm trying to run, which contains 7 tests. The androidx runner fails on 7/7 tests. But when I run with the custom runner, I get duration 0ms and 0/0 tests.

So it seems like Android isn't detecting this runner. I also get the same results using a random name in the testInstrumentationRunner, like testInstrumentationRunner "not.a.TestRunner"

CodePudding user response：

Do not mix between Instrumentation Tests and Unit Tests:

Unit Tests

Unit tests runs in local JVM and minimizes the execution time. Unit Tests cannot test UI of the app without mocking activity objects. Unit test are used for white box testing for testing code. Most of the time Unit Tests are written by Developers. You don’t need a device connected for execution of Unit Tests.

Instrumentation Tests

Instrumentation tests are used for black box testing. It is used to test GUI of the application along with its functionality in real environment. For execution of Instrumentation tests you need a device /emulator on which the application is first installed and then tests are executed. Automation Testers are involved in writing instrumentation framework.

CodePudding user response：

When testing a library module, you can link the test application in src/androidTest/AndroidManifest.xml:

<manifest
    xmlns:android="http://schemas.android.com/apk/res/android">
    <application
        android:name="com.my.app.ApplicationTest"/>
</manifest>