Wen Ching's Blog

Test a C# exe without the source code

I has writen a simple illustration as below, in order to test a simple C# program 

that accepts input and perform factorial calculation to it. I am hoping to hear feedback from you.

I will try to be specific and explain in steps by steps. 

General Assumption 1: this is a C# console application called Fac.exe

General Assumption 2: only on .NET Framework 1.1 and Visual Studio .NET 2003

There are 2 possible ways which I can think of at the moment.

1) 

Assumption 1: There is a public method in this application. You can check it through .NET Reflector by Lutz Roeder.

1. Rename Fac.exe to Fac.dll

2. Create a C# console application and add references to nunit.framework and Fac.dll

3. Optional: You can use object browser in Visual Studio .NET 2003 to look into Fac.dll for available information.

4. Place [TestFixture] attribute at the main public class.

5. Create a new void method called TestFacMethod. Place a [Test] attribute above this method.

6. Place your assertion within this method to check the factorial function.

7. Build this project, and run the nunit-gui program.

8. You can test it.

A simple snippet of the test elaborates above:

            [Test]

            public void TestThis()

            {

// Assuming Calc is the class for Fac.exe, and Fac(long input) is the public static method

                  long result = Calc.Fac(5);

                  Assert.AreNotEqual(0, result);

            }

2)

Assumption 2: What if there is no public method, which will be difficult to use NUnit?

1. Basically you can write a simple C# Console application that utilizes the System.Diagnostics.Process to create a new process to run Fac.exe.

2. You can pass the argument you want to Fac.exe

3. You can redirect the standard output and error into a string (or a text file) to be displayed later at the console.  

A simple snippet to elaborate as above:

                  Process mProcess = new Process();

                  mProcess.StartInfo.FileName = "Fac.exe";

                  mProcess.StartInfo.UseShellExecute = false;

                  mProcess.StartInfo.CreateNoWindow = true;

                  mProcess.StartInfo.RedirectStandardInput = true;

                  mProcess.StartInfo.RedirectStandardOutput = true;

                  mProcess.StartInfo.RedirectStandardError = true;

                  mProcess.Start();

                  StreamWriter input = mProcess.StandardInput;

                  StreamReader output = mProcess.StandardOutput;

                  StreamReader error = mProcess.StandardError;

                  input.Write("5" + System.Environment.NewLine);

                  input.Write("exit" + System.Environment.NewLine);

                  string sOutput = output.ReadToEnd();

                  string sError = error.ReadToEnd();

                  if (!mProcess.HasExited)

                        mProcess.Kill();

                  Console.WriteLine("Exited Code: " + mProcess.ExitCode);

                  input.Close();

                  output.Close();

                  error.Close();

                  mProcess.Close();

                  // Display at the console

                  Console.WriteLine("[Start] " + sOutput + " [End]" + System.Environment.NewLine);

                  Console.WriteLine("[Start] " + sError + " [End]" + System.Environment.NewLine);

Cheers.