Question

I need to cover some tests with JUnit. My method returns java.io.File. What are the attributes I need to check?

• check file size?
• check file name?
• check …?

How do you write JUnit tests for methods, that operate with files? Is there any frameworks?

Answer 1

Method returns java.io.File. What is the best way to check it?

There is no “best way”. It completely depends on what the file is supposed to contain, and what you NEED TO test.

In different situations I might test that:

• the File argument is non-null,
• the filepath encoded by the File has a given value,
• the corresponding file exists,
• the corresponding file has given length or line count,
• the corresponding file contains a given string (or strings) or pattern (patterns),
• the file contents exactly matches a file of expected output,
• the file contents parses to the same data structure as another file, or
• the file contents parses to some data structure that some other properties.