     var variableDict = [String:Double]()
     
     //Tests for Assignment 1
-    func testCalculatorBrainBasicOperands(){
+    func testCalculatorBrainBasicOperandsHappyPath(){
         brain.clear()
         // 7 + --> 7, true, "7 + "
         brain.setOperand(7)

        var brainResult = brain.evaluate(using: variableDict)
        XCTAssertEqual(brainResult.result, 3.0)
        XCTAssertNil(variableDict["M"])
        XCTAssertEqual(brainResult.description, "√(9+M)")

        //7 →M --> display = 4, M = 7, desc = √(9+M)
        // sets the value of 7 into M
        brain.setOperand(7)
        variableDict.updateValue(7, forKey:"M")
        brainResult = brain.evaluate(using: variableDict)
        XCTAssertEqual(brainResult.result, 4.0)
        XCTAssertEqual(7, variableDict["M"])
        XCTAssertEqual(brainResult.description, "√(9+M)")
        
        // + 14 = --> display = 18, M = 7, desc ="√(9+M) + 14"
        brain.performOperation("+")

        XCTAssertFalse(brainResult.isPending)
        XCTAssertEqual(brainResult.description, "73")
        
        // 4 x π = --> 12.5663706143592, false, "4 + π "
        brain.clear()
        brain.setOperand(4)
