How to mock a file with EasyMock?

Question

I have recently been introduced to EasyMock and have been asked to develop some unit tests for a FileMonitor class using it. The FileMonitor class is based on a timed event that wakes up and checks for file modification(s) in a defined list of files and directories. I get how to do this using the actual file system, write a test that writes to a file and let the FileMonitor do its thing. So, how do I do this using EasyMock? I just don't get how to have EasyMock mock the file system.

Thanks, Todd

Answer 1

Something along the lines of:

import static org.easymock.classextension.EasyMock.*;

File testDir = createMock(File.class);
expect(testDir.lastModified()).andReturn(10L);
// more expectations
replay(testDir);
// create a FileMonitor watching testDir
// run the method which gets invoked by the trigger     
verify(testDir);

Answer 2

Have a look at the excellent (and concise) user guide. You might reconsider using EasyMock though - most people are currently using or in the process of switching to the more advanced and more actively developed Mockito (inspired by EasyMock).