assertj for java 7

android/app/build.gradle

@@ -60,5 +60,5 @@ dependencies {
     // tests
     testCompile "junit:junit:4.12"
     testCompile "org.robolectric:robolectric:3.1.4"
-    testCompile 'org.assertj:assertj-core:3.5.2'
+    testCompile 'org.assertj:assertj-core:2.5.0'
 }