Tests fail on windows

[hasufell]

Reproducibly.

Test suite test: RUNNING...
Tests
  openNewBinaryFile:                          FAIL
    tests\test.hs:35:
    Does not match template: tes7ABD.txt
  mkTempFileName:                             OK
  withSystemTempFile:                         FAIL
    tests\test.hs:64:
    Does not match template: tes7ABE.txt
  withSystemTempDirectory:                    OK
  writeSystemTempFile:                        OK
  emptySystemTempFile:                        OK
  withSystemTempFile returns absolute path:   OK
  withSystemTempDirectory is not interrupted: OK (0.21s)

2 out of 8 tests failed (0.24s)
Test suite test: FAIL
Test suite logged to: C:\Users\hasuf\temporary\dist-newstyle\build\x86_64-windows\ghc-8.10.5\temporary-1.3\t\test\test\temporary-1.3-test.log

[hasufell]

The test code makes incorrect assumptions and the documentation is vague.

The Win32 functions are clearly documented to have this behavior though: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-gettempfilenamew

The null-terminated prefix string. The function uses up to the first three characters of this string as the prefix of the file name. This string must consist of characters in the OEM-defined character set.

[hasufell]

The behavior may be different depending on which I/O subsystem is active, but I'm getting errors trying with native IO manager.

haskell/win32#177

[hasufell]

https://gitlab.haskell.org/ghc/ghc/-/merge_requests/5974