How to include both valid and invalid test case

Question

Hi All,

I have a simple testmethod

public double Divide(double numerator, double denominator)

{ if (denominator == 0) { throw new NullReferenceException("Cannot divide by zero."); } return numerator / denominator;

}

Now my Testcase data file looks like this

<TestCase>
    <Numerator>-2.5</Numerator>
    <Denominator>1</Denominator>
    <ExpectedResult>-2.5</ExpectedResult>
</TestCase>
<TestCase>
    <Numerator>55</Numerator>
    <Denominator>5</Denominator>
    <ExpectedResult>11</ExpectedResult>
</TestCase>
<TestCase>
    <Numerator>5</Numerator>
    <Denominator>0</Denominator>
    <ExpectedResult>DivideByZeroException</ExpectedResult>
</TestCase>

What should be the way to include all these testcases into a single test method. My basic problem is to handle the exception test method. I know I can use [ExpectedException(typeof(DivideByZeroException)] attribute into test method, but in that case this method will not fit for other 2 test csaes.

Could someone please help me how I can accommodate all these test cases into a single method. Thanks in advance

Cheers, Pritam

Answer 1

You could catch the DivideByZeroException inside you test method and then Assert.Sucess(); (inside the catch block)

Answer 2

Something like this:

public void TestQuotients() {
    try {
      // do the test which causes divide by 0
      int x = 0;
      int y = 10 / x;

      Assert.Fail("should have gotten exception");
    }
    catch (DivideByZeroException e) {
      // expected behavior
    }

    try {
      // do the next test which causes divide by 0
      int k = 0;
      int t = 100 / k;
      Assert.Fail("should have gotten exception");
    }
    catch (DivideByZeroException e) {
      // expected behavior
    }

    // this test doesn't cause exception
    double x = 100;
    double y = 10;
    Assert.AreEqual(10,x/y,"The quotient is wrong.");
}