JUnit4 - AssertionFailedError:未找到任何测试

我正在使用AndroidJUnitRunner和Espresso.

我写了一个简单的测试但总是收到这个例外.根据Stackoverflow的回答,问题是弄乱JUnit3和JUnit4,但我从未在我的项目中使用过JUnit3.

junit.framework.AssertionFailedError:在com.walletsaver.app.test.espresso.SignUpPopupTest中找不到测试

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 mActivityRule =
            new ActivityTestRule<>(LoginActivity.class);

    @Test
    public void checkSignUpPopup() throws Exception {
        onView(withText("Sign Up")).perform(click());
    }
}

运行配置:

输出:

我发现了这个问题.它build.gradle在主模块中丢失了代码.如果你有这个问题,我建议先添加这一行:

android {
    ...

    defaultConfig {
        ...

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