C# Unit Test MOQ Method for GetAccounts not being tested

I'm learning to create unit test methods for a bank application as part of my assignment and I'm having an issue:

The test method GetAccounts() is not being tested for some reason on Visual Studio. the Output message I get is "Discover test finished : 0 found" This is the test method block below.

   [TestMethod]
    public void GetAccounts()
    {
        var testAccount = this.MockDatabase.GetAccounts();
        Assert.IsNotNull(testAccount);
        Assert.AreEqual(4, testAccount.Count);
    }

How can I make Visual Studio discover the test and give me some result?

If anyone wants me to post more of my codes, and not just the snippet above let me know. I'm happy to give you more info.