Jump.CredoChecks.AssertReceiveTimeout (Jump.CredoChecks v0.4.0)

Basics

This check has a base priority of normal and works with any version of Elixir.

Explanation

Tests should rely on the default :ex_unit :assert_receive_timeout rather than specifying their own. Custom timeouts inflate suite duration when the message never arrives and tend to drift higher over time as people paper over flaky tests.

# ❌ Bad — explicit timeout
assert_receive :foo, 1_000

# ✅ Good — rely on the configured default
assert_receive :foo

If you want to be able to specify a longer timeout than default, configure this check with a min_assert_receive_timeout to enforce a floor; any literal timeout at or above the minimum will be allowed, and omitting the timeout entirely (falling back to ExUnit's default) is always allowed.

Additionally, you can configure max_refute_receive_timeout to cap how long a refute_receive is allowed to block. Because refute_receive always waits its full timeout (including ExUnit's default when none is specified), the timeout sets a minimum bound on how long the test takes to run. When this param is set, every refute_receive must specify an explicit literal timeout at or below the configured maximum — bare refute_receive calls are flagged too, since they fall back to a default that also blocks the test.

Check-Specific Parameters

Use the following parameters to configure this check:

:min_assert_receive_timeout

If set, allows explicit assert_receive timeouts that are an integer literal greater than or equal to this value. Defaults to nil (no explicit timeout allowed). As with the built-in timeout type, units are milliseconds.

This parameter defaults to nil.

:max_refute_receive_timeout

If set, flags refute_receive calls whose timeout is an integer literal greater than this value, whose timeout cannot be statically verified, or which omit an explicit timeout entirely. Defaults to nil (no refute_receive timeout is flagged). As with the built-in timeout type, units are milliseconds.

This parameter defaults to nil.

General Parameters

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.