Test.HUnit.Diff

Very basic support for diffing with HUnit.

Limitations:

• Prints the whole value, not just the difference with a few lines of context.
• Relies on the similarity of pretty-printed show results which sorta-kinda works much of the time but may sometimes highlight differences too eagerly.
• Always colors the differences for ANSI terminals, regardless of output target.

Despite these limitations, I find it more useful than HUnit's defaults.

Documentation

(@?==) :: (Eq a, Show a) => a -> a -> Assertion

Like @?= but producing a colored diff on failure.

(@==?) :: (Eq a, Show a) => a -> a -> Assertion

Like @=? but producing a colored diff on failure.