Bazel

MODULE.bazel

bazel_dep(name = "mutrim", version = "0.1.0")
local_path_override(module_name = "mutrim", path = "../mutrim")  # until it is published

# BUILD.bazel: mirror the package's go_test
load("@mutrim//:defs.bzl", "mutation_test")

mutation_test(
    name = "mutant_calc",
    srcs = ["calc_test.go"],
    embed = [":calc"],
    embedsrcs = ["testdata/golden.txt"],   # optional; files the tests' //go:embed name
    operators = ["default", "-constant"],  # optional; see `mutrim gen -operators`
    match = "^Compute",                    # optional; the gen filters, per attribute
    exclude_files = ["_gen\\.go$"],
    arid = ["(*Metrics).Observe"],         # optional; extends the built-in arid rules
    subtests = True,                       # optional; `mutrim run -subtests`
    confirm_kills = 3,                     # optional; `mutrim run -confirm-kills`
    confirm_baseline = 3,                  # optional; `mutrim run -confirm-baseline`
    extra_tests = ["//app:app_test"],      # optional; `mutrim run -extra-test`
    threshold = 0.8,                       # optional; `mutrim run -threshold`
    sample = 0.2,                          # optional; `mutrim run -sample`
    seed = 42,                             # optional; `mutrim run -seed`
    jobs = 4,                              # optional; `mutrim run -jobs`, pair with tags
    min_timeout = "2s",                    # optional; `mutrim run -min-timeout`
    tags = ["cpu:4"],
    shard_count = 4,
)

bazel test //pkg:mutant_calc builds the package once with every mutant embedded, runs the tests against it (mutant_calc_schemata_test, which must pass like the original tests), then re-executes that binary once per mutant against the tests reaching it and writes report.json, minimize.json and the Stryker mutation-report.json / mutation-report.html to the test’s undeclared outputs (bazel-testlogs/pkg/mutant_calc/test.outputs/, one directory per shard; pass the shards’ reports together to mutrim minimize or mutrim report for a whole-package verdict). Mutants are generated hermetically: the rule type-checks the library against the export data rules_go compiled for its dependencies, so no go command runs inside the sandbox. extra_tests names the go_tests of packages importing the library: each is relinked against the schemata library (mutant_calc_extra0, …), recompiling every package between the test and the library as go_test itself does for external tests, and its tests run against the mutants too; the target must be visible to the mutation_test’s package, and race cannot be set with it yet. Passing --test_env=MUTRIM_IN_DIFF=$PWD/pr.diff scopes the run to a diff, as above.

//go:embed works on both sides: the library’s embedsrcs come with embed (rules_go resolves the patterns against the embedded files, wherever the schemata sources live), and the tests’ are passed as embedsrcs, as to go_test. Not supported yet: cgo packages. examples/ dogfoods the macro; run bazel test //... here to see it work.