Seems that dropDrive on windows only drops eg c:/ but not a leading /
while on linux, it does drop a leading / (which is what it considers
to be equivilant to a drive letter. I had been relying on it to drop
both. So need to drop leading directory separators.
Also, if the quickcheck generated input is eg "c:c:c:c:foo",
dropDrive will only drop the first one, leaving a path that's
still not relative. So instead of using dropDrive, just remove the
colons from the path.
It was just slapping on a path separator to the front of the path to
make it absolute, but on windows, a path like "//foo/bar" actually
has a network "drive" of "//foo" and so that broke the test case.
Since "a:foo" is a somehow relative path on windows
(who knows how), drop any drive from the input. But dropDrive also drops
any leading path separator, making the input path relative. So now
it should be safe to slapp on a leading path separator.
This was not a good test, it broke the requirement that
relPathDirToFileAbs take absolute paths. And it failed when the two
input paths were eg, the same but differently normalized.
Replaced with some tests of the real basics of that function.
All properties changed to use them, except for
prop_encode_c_decode_c_roundtrip, which already filtered to ascii
for other reasons.
A few modules had to be split out, because Setup does not build-depend
on QuickCheck.
