Round the results of some floating-point doctests

[RyanGlScott]

This should make the results consistent enough to work across multiple implementations of libc. Fixes #73.

[RyanGlScott]

@nh2, can you confirm if the tests pass for you with musl using this PR?

[nh2]

@RyanGlScott I can't tell, I get this odd import error:

Test suite doctests: RUNNING...
/build/source/src/Numeric/AD.hs:177: failure in expression `import Numeric.AD.Internal.Doctest'
expected: 
 but got: 
          <no location info>: error:
              Could not find module ‘Numeric.AD.Internal.Doctest’
              Perhaps you meant
                Numeric.AD.Internal.Dense (from ad-4.3.5)
                Numeric.AD.Internal.Tower (from ad-4.3.5)
                Numeric.AD.Internal.Forward (from ad-4.3.5)

Even with nh2@97a3bc0 applied on top. The parent commit of this PR, commit be71c10, continues to show the doctest test failure, so it really seems that this PR somehow results in Numeric.AD.Internal.Doctest not being visible.

Any idea?

[nh2]

Ah, the line

Compiling Numeric.AD.Internal.Doctest ( src/Numeric/AD/Internal/Doctest.hs, dist/build/Numeric/AD/Internal/Doctest.o )

was even missing from the compiler output.

I suspect this is because I tried to try your PR using

ad = pkgs.haskell.lib.overrideCabal super.ad (old: {
  src = pkgs.fetchFromGitHub {
    owner = "nh2";
    repo = "ad";
    rev = "97a3bc0883b97604351396f884df847ebb1b284c"; # fixed
    sha256 = "1q707cid6wgbz9n3mkvwq2ccq14sbmyajakv9dxk830vwa4s7pnw"; # fixed
  };
});

and that keeps the old cabal file, with its modules?

Using callCabal2nix made it work:

      ad = self.callCabal2nix "ad" (pkgs.fetchFromGitHub {
        owner = "ekmett";
        repo = "ad";
        rev = "d35d76738498dd2cedebeaa9a03c471fd5e5e2da";
        sha256 = "0c7wca9xysyf973nxr9vwkd512xkmp6nwjg9grb4s434sfjxhfmb";
      }) {};

This works for your PR directly, without my extra patch on top that puts it into exposed-modules.

I've tested it on nh2/static-haskell-nix@eda03f4 with command NIX_PATH=nixpkgs=https://github.com/NixOS/nixpkgs/archive/88ae8f7d.tar.gz nix-build --no-link survey/default.nix -A haskellPackages.ad.

can you confirm if the tests pass for you with musl using this PR?

Yes. 👍

[RyanGlScott]

Excellent! I'll prepare a Hackage release with this fix soon.

[RyanGlScott]

ad-4.3.6