ASP Classic Compiler: the unit testing framework is released

In my previous post, I stressed the importance to have a unit testing framework to move forward with this project. I was facing the decision whether to use NUnit or MSTest. After some thoughts, I came to the conclusion that the choice of unit testing framework is not critical, at least for now. For a language project, unit testing usually falls into two categories: the testing of a parser and the testing of generated code. For parser testing, most of work lies in comparing AST generated by the parser with the expected AST. Paul Vick has an excellent framework in his VBParser work. For testing of the generated code, it is best to have a unit testing framework that is self-contained in the target language so that is can most accurately test the semantics of the language. For example, Javascript has the QUnit framework and ASP Classic has the ASPUnit framework.

So I went ahead to release my own unit testing framework for VBScript. I created an interface called IAssert that has the following methods:

        void AreEqual(object expected, object actual);

        void AreEqual(object expected, object actual, string message);

        void AreNotEqual(object notExpected, object actual);

        void AreNotEqual(object notExpected, object actual, string message);

        void Fail();

        void Fail(string message);

        void IsFalse(bool condition);

        void IsFalse(bool condition, string message);

        void IsTrue(bool condition);

        void IsTrue(bool condition, string message);

These are minimum set of method often found in most of unit testing frameworks. We can always add more when needed. Note that I did not have IsEmpty or IsNothing methods. That is because I believe we should use the language built-in method to best reflect the language semantics. For example, instead of having an IsEmpty method in the testing framework, we should use IsTrue(IsEmpty(myVar)) where we are using the VBScript built-in function.

In environments that we have control over the host, the host will supply an Assert object that can route the testing results to one of the existing unit testing framework, such as NUnit, so that we can reuse the test runners and report functionalities. In the environments that we do not have control of the host, we can supply an Assert class in VBScript itself, much like what ASPUnit does.

If you look at my VBScriptTest project, you will notice that it uses NUnit framework. It has a single NUnit test case that walks the entire hierarchy under the VBScripts folder. When we need to write a new test case, we just simply add a .vbs file under the VBScripts folder. The following is an example VBScript unit test case:

dim a
Assert.IsTrue(IsEmpty(a), "Unassigned variable must be empty")

Because I have use a single NUnit test case to run all the VBScripts, the message parameter is an important parameter to distinguish the test case in the situation of failed test case.