helpers/mkEval

Declare a suite of pure Nix evaluation tests as an eval check.

An eval check is plain data — no derivation, no store access. Tests are evaluated lazily, one attribute per test, so runners such as nrc can shard them across nix-eval-jobs workers. Use mkEntries to compute the per-test results.

Registered in resultChecks.checks, an eval check displays as a suite with one entry per test. Use this for testing pure Nix functions. For testing shell commands or build-time behaviour, use mkResult or mkSnapshot.

Type

mkEval :: AttrSet -> EvalCheck

Arguments

tests

Attribute set of test cases. Each entry must have expr (the value under test) and expected (the expected value). Unlike lib.debug.runTests, every attribute is a test regardless of its name.

Example

resultChecks.checks.my-lib = mkEval {
  testAdd = {
    expr = myLib.add 1 2;
    expected = 3;
  };
};