tests/Commands.hs: add trivial tests for playback commands
tests/Commands.hs: add trivial tests for playback commands

Adds tests for crossfade, pause, next, previous, random, repeat, setVolume and
volume. 'seek' is the only remaining playback command without a test.

darcs-hash:20080201143753-928c4-092e28b5fad52c73d12deb3a9de7261ea9d1c1d1.gz

sol/libmpd-haskell,beni55/libmpd-haskell