   }
   
   func testOptionalBool() {
-    let key = "boolKey"
+    let key = UUID().uuidString
     XCTAssertTrue(!userDefaults.hasKey(key))
     
     userDefaults.set(true, forKey: key)

  }

  func testOptionalFloat() {
    let key = "floatKey"
    XCTAssertTrue(!userDefaults.hasKey(key))
    
    userDefaults.set(10.1, forKey: key)

  }

  func testOptionalInt() {
    let key = UUID().uuidString
    XCTAssertTrue(!userDefaults.hasKey(key))
    
    userDefaults.set(10, forKey: key)
