Handle expected exception in unit test in MSTest

Question

I am testing DoingSomething() method with the following test method-

[TestMethod()]
[ExpectedException(typeof(ArgumentException),"Invalid currency.")]
public void ConvertCurrencyTest_ExhangeRate()
{
    try
    {
        DoingSomething();
    }
    catch (ArgumentException Ex)
    {
    }
    catch (Exception Ex)
    {
        Assert.Fail();
    }
}

Test result says that DoingSomething() did not throw an exception. But it thrown exception indeed.

What did I miss here?

Answer 1

You are consuming the exception in your try/catch so it is not bubbling up to be caught by the test.

Remove the try/catch and let the test harness handle the exception. Any other exception would naturally cause the test to fail anyway.

[TestMethod()]
[ExpectedException(typeof(ArgumentException),"Invalid currency.")]
public void ConvertCurrencyTest_ExhangeRate() {       
    DoingSomething();        
}