Mocking IO operations in Nunit using Typemock

Question

I have the following method.

public string CreateFile(string path, string fileName)
{
    string fullPath = path + "ExportedFiles\\";
    if (Directory.Exists(fullPath))
    {
        DirectoryInfo dir = new DirectoryInfo(fullPath);
        foreach (FileInfo fi in dir.GetFiles())
        {
            fi.Delete();
        }
    }
    else
    {
        Directory.CreateDirectory(fullPath);
    }
    string filePath = fullPath + fileName;
    return filePath;
}

I attempted to used the following in my test case.

[Test, Isolated] 
public void TestCreateFileIfPathExists() 
{ 
    Isolate.WhenCalled(() => System.IO.Directory.Exists("gsgs")).WillReturn(true);
    Isolate.WhenCalled(() => testMyClass.CreateFile(@"D:\testFolder\","TestFile")).CallOriginal(); 
    string result = testMyClass.CreateFile(@"D:\testFolder\", "TestFile");
    Assert.AreEqual("D:\\testFolder\\ExportedFiles\\TestFile", result);
}

It's throwing the following typemock exception.

TypeMock.TypeMockException : * No method calls found in recording block. Please check: * Are you trying to fake a field instead of a property? * Are you are trying to fake an unsupported mscorlib type?

Is there any way to solve this?

possible duplicate of [How do you mock out the file system in C# for unit testing?](http://stackoverflow.com/questions/1087351/how-do-you-mock-out-the-file-system-in-c-sharp-for-unit-testing) — Ryan Gates, Jul 01 '13 at 13:46
but they haven't mentioned how to achieve this using Typemock — user2435880, Jul 01 '13 at 14:46
Please always add additional information or clarifications to your questions in the question itself rather than in the comments. This will help future users/viewers understand the question. — Ryan Gates, Jul 01 '13 at 15:42
Please always copy the entire error message(even if it includes parts you don't consider relevant). — Ryan Gates, Jul 02 '13 at 19:17

score 1 · Answer 1 · answered Jul 02 '13 at 19:17

1

If you look at the last question of the exception that you are getting,

* Are you are trying to fake an unsupported mscorlib type?

there is actually a web address after that in the exception, which reads

See supported types here: http://www.typemock.com/mscorlib-types

When you go there, you will notice:

enter image description here

Notably absent from this list is the System.IO.Directory class, which appears to not be supported TypeMock as of this writing. This is the line that is causing your error.

answered Jul 02 '13 at 19:17

Ryan Gates

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@user2435880 The only way that I am aware of is to create a layer of abstraction between your code and the code that goes to disk like in the [How do you mock out the file system in C# for unit testing?](http://stackoverflow.com/questions/1087351) question. – Ryan Gates Jul 05 '13 at 03:46

Mocking IO operations in Nunit using Typemock

1 Answers1