JUnit4 - AssertionFailedError: No tests found

Question

I'm using AndroidJUnitRunner with Espresso.

I wrote a simple test but always receive this exception. According to Stackoverflow answers, the problem is messing up the JUnit3 and JUnit4 but I have never used JUnit3 in my project.

junit.framework.AssertionFailedError: No tests found in com.walletsaver.app.test.espresso.SignUpPopupTest

package com.walletsaver.app.test.espresso;  import android.support.test.rule.ActivityTestRule; import android.support.test.runner.AndroidJUnit4; import android.test.suitebuilder.annotation.SmallTest;  import com.walletsaver.app.activity.LoginActivity;  import org.junit.Rule; import org.junit.Test; import org.junit.runner.RunWith;  import static android.support.test.espresso.Espresso.onView; import static android.support.test.espresso.action.ViewActions.click; import static android.support.test.espresso.matcher.ViewMatchers.withText;  @RunWith(AndroidJUnit4.class) @SmallTest public class SignUpPopupTest {      @Rule     public ActivityTestRule<LoginActivity> mActivityRule =             new ActivityTestRule<>(LoginActivity.class);      @Test     public void checkSignUpPopup() throws Exception {         onView(withText("Sign Up")).perform(click());     } } 

Run configuration:

Output:

Answer 1

I found the problem. It was missed code in build.gradle in the main module. If you have this problem I advise to start with adding this line:

android {     ...      defaultConfig {         ...          testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'     } ... }