espresso - how to declare path for custom test runner

Question

I have created a custom test runner for espresso and it looks like this:

    public class MyRunner extends AndroidJUnitRunner {
  @Override
  public Application newApplication(ClassLoader cl, String className, Context context)
      throws Exception {
    return super.newApplication(cl, MyCustomEspressoApplication.class.getName(), context);
  }
}

i have placed the class inside of the androidTest folder. Is that ok ?

Now i went to the gradle file to update the test runner and i put in this:

testInstrumentationRunner "com.mobile.myapp.base.MyRunner"

(is this path ok ? remember i put it in the androidTest folder).

and one of my tests classes structure looks like this:

    @RunWith(AndroidJUnit4.class)

public class AuthenticationActivityTest {
//....

@Test
   public void signupWithFacebook() {//...}
}

but when i run the test android studio says it cant find the test runner. here is the exact error i get:

   Test running failed: Unable to find instrumentation info for:
 ComponentInfo{com.mobile.myapp.labs.test/android.support.test.runner.AndroidJUnitRunner}

Please again note my custom test runner is located here: androidTest-->java-->com-->mobile-->myapp-->base-->MyRun‌​ner.java

UPDATE: below is the custom testrunner i am trying to use:

    package com.mobile.myapp.base;

import android.support.test.runner.AndroidJUnitRunner;

import com.squareup.rx2.idler.Rx2Idler;

import io.reactivex.plugins.RxJavaPlugins;



public class MyRunner extends AndroidJUnitRunner {
    @Override public void onStart() {
        RxJavaPlugins.setInitComputationSchedulerHandler(
                Rx2Idler.create("RxJava 2.x Computation Scheduler"));
        // etc...

        super.onStart();
    }
}

when i check the android manifest generated i see this :

<instrumentation
       android:name="com.mobile.myapp.base.MyRunner"
       android:functionalTest="false"
       android:handleProfiling="false"
       android:label="Tests for com.mobile.myapp.labs"
       android:targetPackage="com.mobile.myapp.labs" />

   <application>
       <uses-library android:name="android.test.runner" />
   </application>

Answer 1

finally figured this out after hours of effort. This combination got it it work:

uninstall the current application. delete all testing configurations in run area by clicking on run -->edit configurations and deleting the entire instrumentation testing configurations and then starting again. Here is an image:

Answer 2

Please again note my custom test runner is located here: androidTest-->java-->com-->mobile-->myapp-->base-->MyRun‌​ner.java

then testInstrumentationRunner is wrong. The path has to match the location of the file

testInstrumentationRunner "com.mobile.myapp.base.MyRunner"

should do it