# `mix affected.map`
[🔗](https://github.com/mnox/mix_affected/blob/v0.1.0/lib/mix/tasks/affected.map.ex#L1)

Builds the test map `mix affected.files` and `mix affected.test` select
with, at `_build/test/mix_affected/test_map.etf` or `--map <path>`. Those
tasks build it themselves when it is missing. Run with `MIX_ENV=test`.

Compiles the project and starts it as `mix test` does, requires
`test_helper.exs` and every test file with a compiler tracer registered,
and runs no test. See `MixAffected.TestMap.Builder` for the fallbacks when
a test file fails to require, or declares an `affected_by` glob that is
malformed or names a directory (that file always runs, with a warning). A
summary goes to stderr.

Exit status: 0 when written, 1 on a usage error (including an umbrella
root, which is not supported), 2 when the map could not be built.

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*Consult [api-reference.md](api-reference.md) for complete listing*