Unit testing code with a file system dependency

Question

I am writing a component that, given a ZIP file, needs to:

1. Unzip the file.
2. Find a specific dll among the unzipped files.
3. Load that dll thro

Answer 1

I am reticent to pollute my code with types and concepts that exist only to facilitate unit testing. Sure, if it makes the design cleaner and better then great, but I think that is often not the case.

My take on this is that your unit tests would do as much as they can which may not be 100% coverage. In fact, it may only be 10%. The point is, your unit tests should be fast and have no external dependencies. They might test cases like "this method throws an ArgumentNullException when you pass in null for this parameter".

I would then add integration tests (also automated and probably using the same unit testing framework) that can have external dependencies and test end-to-end scenarios such as these.

When measuring code coverage, I measure both unit and integration tests.