tighter mock

s3_test.clj

(deftest get-file-metadata-test
  (let [example-bucket "some-bucket"
        example-filename "some-file"        
        example-metadata {:example "valid metadata"}]
    (testing "should return file metadata in case file exists"
      (with-redefs [s3/get-object (fn [& {:keys [bucket-name key]}] 
                                    (when (and 
                                            (= bucket-name example-bucket) 
                                            (= key example-filename)) 
                                      example-metadata))]
        (is (= example-metadata (get-file-metadata example-bucket example-filename)))))))