Switch to mockito-core from mockito-all

build.gradle

     compile group: 'com.google.code.findbugs', name: 'jsr305', version: '3.0.0'
 
     testCompile group: 'junit', name: 'junit', version: '4.12'
-    testCompile group: 'org.mockito', name: 'mockito-all', version: '1.10.17'
+    testCompile group: 'org.mockito', name: 'mockito-core', version: '1.10.17'
     testCompile group: 'com.google.jimfs', name: 'jimfs', version: '1.0'
 }