Failing unit tests for FileAssert.Exists
Simple implementation of FileInfo.Exists without using constraints
Removed unused using statements
Added a FileExistsConstraint
Added FileAssert.DoesNotExist()
Resharper put a using statement before a pragma. Fixed it.
Fixed spacing in methods
Update FileAssertTests.cs

Removed the extra "Exist" noted by simone
Merge pull request #130 from nunit/issue-111

Add FileAssert.Exists and FileAssert.DoesNotExist

Just for the experience, I used the GitHub online edit to fix the duplicate "Exist" noted by Simone and committed. If it breaks, it's my fault. :-)