Fix ApplicationTest.java

app/build.gradle

@@ -71,6 +71,9 @@ dependencies {
     implementation 'com.github.PhilJay:MPAndroidChart:v3.0.0-beta1'
     implementation 'androidx.multidex:multidex:2.0.1'  //with androidx libraries
 
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test:runner:1.5.2'
+
     def work_version = '2.9.0'
     implementation "androidx.work:work-runtime:$work_version"
     implementation "androidx.work:work-runtime-ktx:$work_version"

app/src/androidTest/java/org/secuso/privacyfriendlyactivitytracker/ApplicationTest.java

@@ -1,13 +1,20 @@
 package org.secuso.privacyfriendlyactivitytracker;
 
-import android.app.Application;
-import android.test.ApplicationTestCase;
+import static junit.framework.TestCase.assertEquals;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
 
 /**
  * <a href="http://d.android.com/tools/testing/testing_android.html">Testing Fundamentals</a>
  */
-public class ApplicationTest extends ApplicationTestCase<Application> {
-    public ApplicationTest() {
-        super(Application.class);
+@RunWith(AndroidJUnit4.class)
+public class ApplicationTest {
+    @Test
+    public void instrumentationTest() throws Exception {
+        assertEquals("org.secuso.privacyfriendlyactivitytracker", InstrumentationRegistry.getInstrumentation().getTargetContext().getPackageName());
     }
 }