Test.Tasty.Silver

This module provides a simplified interface. If you want more, see Test.Tasty.Silver.Advanced.

Note about filenames

They are looked up in the usual way, thus relative names are relative to the processes current working directory. It is common to run tests from the package's root directory (via cabal test or stack test), so if your test files are under the tests/ subdirectory, your relative file names should start with tests/ (even if your test.hs is itself under tests/, too).

Note about line endings

The best way to avoid headaches with line endings (when running tests both on UNIX and Windows) is to treat your golden files as binary, even when they are actually textual.

This means:

• When writing output files from Haskell code, open them in binary mode (see openBinaryFile, withBinaryFile and System.IO.hSetBinaryMode). This will disable automatic \n -> \r\n conversion on Windows. When using ByteString, note that Data.ByteString and Data.ByteString.Lazy use binary mode for writeFile, while Data.ByteString.Char8 and Data.ByteString.Lazy.Char8 use text mode.

• Tell your version control not to do any newline conversion for golden files. For git, check in a .gitattributes file with the following contents (assuming your golden files have .golden extension):

*.golden	-text

On its side, `tasty-silver` reads and writes files in binary mode, too.

Why not let Haskell/git do automatic conversion on Windows? Well, for instance, tar will not do the conversion for you when unpacking a release tarball, so when you run e.g. stack install your-package --tests, the tests will be broken.

As a last resort, you can strip all \r characters from both arguments in your comparison function when necessary. But most of the time treating the files as binary does the job.