nixpkgs/lib/path/tests/prop.nix
2023-01-03 13:21:06 +01:00

61 lines
2.5 KiB
Nix

# Given a list of path-like strings, check some properties of the path library
# using those paths and return a list of attribute sets of the following form:
#
# { <string> = <lib.path.subpath.normalise string>; }
#
# If `normalise` fails to evaluate, the attribute value is set to `""`.
# If not, the resulting value is normalised again and an appropriate attribute set added to the output list.
{
# The path to the nixpkgs lib to use
libpath,
# A flat directory containing files with randomly-generated
# path-like values
dir,
}:
let
lib = import libpath;
# read each file into a string
strings = map (name:
builtins.readFile (dir + "/${name}")
) (builtins.attrNames (builtins.readDir dir));
inherit (lib.path.subpath) normalise isValid;
inherit (lib.asserts) assertMsg;
normaliseAndCheck = str:
let
originalValid = isValid str;
tryOnce = builtins.tryEval (normalise str);
tryTwice = builtins.tryEval (normalise tryOnce.value);
absConcatOrig = /. + ("/" + str);
absConcatNormalised = /. + ("/" + tryOnce.value);
in
# Check the lib.path.subpath.normalise property to only error on invalid subpaths
assert assertMsg
(originalValid -> tryOnce.success)
"Even though string \"${str}\" is valid as a subpath, the normalisation for it failed";
assert assertMsg
(! originalValid -> ! tryOnce.success)
"Even though string \"${str}\" is invalid as a subpath, the normalisation for it succeeded";
# Check normalisation idempotency
assert assertMsg
(originalValid -> tryTwice.success)
"For valid subpath \"${str}\", the normalisation \"${tryOnce.value}\" was not a valid subpath";
assert assertMsg
(originalValid -> tryOnce.value == tryTwice.value)
"For valid subpath \"${str}\", normalising it once gives \"${tryOnce.value}\" but normalising it twice gives a different result: \"${tryTwice.value}\"";
# Check that normalisation doesn't change a string when appended to an absolute Nix path value
assert assertMsg
(originalValid -> absConcatOrig == absConcatNormalised)
"For valid subpath \"${str}\", appending to an absolute Nix path value gives \"${absConcatOrig}\", but appending the normalised result \"${tryOnce.value}\" gives a different value \"${absConcatNormalised}\"";
# Return an empty string when failed
if tryOnce.success then tryOnce.value else "";
in lib.genAttrs strings normaliseAndCheck