Specify proper dependency versions.

build.gradle

     repositories.mavenCentral()
 
     dependencies {
-        testCompile group: 'junit', name: 'junit', version: '4.+'
-        testCompile group: 'org.mockito', name: 'mockito-all', version: '1.+'
+        testCompile group: 'junit', name: 'junit', version: '4.12'
+        testCompile group: 'org.mockito', name: 'mockito-all', version: '1.10.17'
     }
 
     task getCredentials << {