Use mockito-core not -all.

build.gradle

@@ -46,7 +46,7 @@ dependencies {
     bundle group: 'com.dmdirc.parser', name: 'common', version: '+', changing: true
 
     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'
 }