Question

我有以下实现，

public interface IMath {
    double Add(double a, double b);
    double Subtract(double a, double b);
    double Divide(double a, double b);
    double Multiply(double a, double b);
    double Factorial(int a);
}

public class CMath: IMath {
    public double Add(double a, double b) {
        return a + b;
    }

    public double Subtract(double a, double b) {
        return a - b;
    }

    public double Multiply(double a, double b) {
        return a * b;
    }

    public double Divide(double a, double b) {
        if (b == 0)
            throw new DivideByZeroException();
        return a / b;
    }

    public double Factorial(int a) {
        double factorial = 1.0;
        for (int i = 1; i <= a; i++)
            factorial = Multiply(factorial, i);
        return factorial;
    }
}

如果计算 n 的因子，我如何测试Multiply()被称为 n 次？

我正在使用NUnit 3和Moq。以下是我已经写过的测试，

[TestFixture]
public class CMathTests {

    CMath mathObj;

    [SetUp]
    public void Setup() {
        mathObj = new CMath();
    }

    [Test]
    public void Add_Numbers9and5_Expected14() {
        Assert.AreEqual(14, mathObj.Add(9, 5));
    }

    [Test]
    public void Subtract_5From9_Expected4() {
        Assert.AreEqual(4, mathObj.Subtract(9, 5));
    }

    [Test]
    public void Multiply_5by9_Expected45() {
        Assert.AreEqual(45, mathObj.Multiply(5, 9));
    }

    [Test]
    public void When80isDividedby16_ResultIs5() {
        Assert.AreEqual(5, mathObj.Divide(80, 16));
    }

    [Test]
    public void When5isDividedBy0_ExceptionIsThrown() {
        Assert.That(() => mathObj.Divide(1, 0),
            Throws.Exception.TypeOf<DivideByZeroException>());
    }

    [Test]
    public void Factorial_Of4_ShouldReturn24() {
        Assert.That(mathObj.Factorial(4), Is.EqualTo(24));
    }

    [Test]
    public void Factorial_Of4_CallsMultiply4Times() {

    }
}

我使用Moq相当新，所以我现在还不太明白。

Answer 1

你需要分离模拟部分和测试部分，因为Moq是关于消除依赖关系，而你的CMath类没有它们！

但基本上你不需要测试，Multiply被称为4次 - 它的内部实现。测试结果:)）

方法1 - 拆分类

创建Separate Factorial类，以便乘法将在单独的界面中。

 public interface IMath {
        double Add(double a, double b);
        double Subtract(double a, double b);
        double Divide(double a, double b);
        double Multiply(double a, double b);      
    }
 public interface IFactorial {
       double Factorial(int a, IMath math);
}

在你的测试中，你可以创建Mock of IMath

[Test]
public void Factorial_Of4_CallsMultiply4Times()
{
    var mathMock = new Mock<IMath>();
    var factorial = new Factorial();
    factorial.Factorial(4, mathMock.Object);
    mathMock.Verify(x => x.Multiply(It.IsAny<double>()), Times.Exactly(4));
}

方法2 - 可选的注入代理

public double Factorial(int a, Func<double,double,double> multiply = null)
{
    multiply = multiply ?? CMath.Multiply;
    double factorial = 1.0;
    for (int i = 1; i <= a; i++)
        factorial = multiply(factorial, i);
    return factorial;
}


[Test]
public void Factorial_Of4_CallsMultiply4Times()
{
    var mathMock = new Mock<IMath>();
    var math = new CMath();
    math.Factorial(4, mathMock.Object.Multiply);
    mathMock.Verify(x => x.Multiply(It.IsAny<double>()), Times.Exactly(4));
}

Answer 2

在您的测试课程中，

using Math.Library;
using System;
using Moq;
using NUnit.Framework;

namespace UnitTests {
[TestFixture]
public class CMathTests {

    CMath mathObj;
    private IMath _math;
    [SetUp]
    public void Setup() {
        mathObj = new CMath();// no need for this in mocking and its a wrong      approach
        _math = new Mock<IMath>();//initialize a mock object
    }

    [Test]
    public void Add_Numbers9and5_Expected14() {
        Assert.AreEqual(14, mathObj.Add(9, 5));
    }

    [Test]
    public void Subtract_5From9_Expected4() {
        Assert.AreEqual(4, mathObj.Subtract(9, 5));
    }

    [Test]
    public void Multiply_5by9_Expected45() {
        Assert.AreEqual(45, mathObj.Multiply(5, 9));
    }

    [Test]
    public void When80isDividedby16_ResultIs5() {
        Assert.AreEqual(5, mathObj.Divide(80, 16));
    }

    [Test]
    public void When5isDividedBy0_ExceptionIsThrown() {
        Assert.That(() => mathObj.Divide(1, 0),
            Throws.Exception.TypeOf<DivideByZeroException>());
    }

    [Test]
    public void Factorial_Of4_ShouldReturn24() {
        Assert.That(mathObj.Factorial(4), Is.EqualTo(24));
    }

    [Test]
    public void Factorial_Of4_CallsMultiply4Times() {
    int count = 0;
    _math.setup(x =>x.Multiply(It.IsAny<Int>(),It.IsAny<Int>())).Callback(() => count++);
    _math.verify(x =>x.Multiply(),"Multiply is called"+ count+" number of times");
    }
}
}

这将适合您的情况。类似地，您必须修改您的每个函数，就像在模拟中一样，如果它实现了接口，则无法实例化类的对象请参阅我已经为接口创建了模拟对象。

要了解有关Moq的更多信息，请访问here

如何使用Moq验证方法被调用了一定次数？

2 个答案:

方法1 - 拆分类

方法2 - 可选的注入代理