Addressed pr comments

mock/app.go

@@ -16,7 +16,7 @@ import (
 // It should work similar to a real app.
 // Make sure rootDir is empty before running the test,
 // in order to guarantee consistent results
-func NewApp(logger log.Logger, rootDir string) (abci.Application, error) {
+func NewApp(rootDir string, logger log.Logger) (abci.Application, error) {
 	db, err := dbm.NewGoLevelDB("mock", rootDir)
 	if err != nil {
 		return nil, err

mock/helpers.go

@@ -22,6 +22,6 @@ func SetupApp() (abci.Application, func(), error) {
 		os.RemoveAll(rootDir)
 	}
 
-	app, err := NewApp(logger, rootDir)
+	app, err := NewApp(rootDir, logger)
 	return app, cleanup, err
 }