Question

The following is a failing unittest explaining a bug I found today:

    [TestMethod]
    public void WFT()
    {
        string configDebug = "false";
        bool configDebugEnabled = bool.TryParse(configDebug, out configDebugEnabled);

        Assert.AreEqual(false, configDebugEnabled);
    }

This is how to make the test go from red to green:

    [TestMethod]
    public void WFT()
    {
        string configDebug = "false";
        bool configDebugEnabled;
        bool.TryParse(configDebug, out configDebugEnabled);

        Assert.AreEqual(true, configDebugEnabled);
    }

I haven’t been able to find the paragraph explaining this in the C# specification but there’s most likely a decent explanation to this behaviour. Can anybody explain to me why the first test is failing?

Answer 1

Because the TryParse method always returns true if the parsing succeeds and false if not. In the first case the parsing succeeds so configDebugEnabled = true which is not what you assert.

Btw the second test will also fail unless you write string configDebug = "true".