go test -run skips subtests: how to fix

TL;DR

-run matches each slash-separated level independently, so go test -run TestSub never matches a subtest nested under TestTop. Use the full path with slashes, go test -run 'TestTop/TestSub', and anchor each level with ^...$ because every segment is an unanchored regex.

Problem

Running go test -run TestLoginValid reports ok with zero tests run even though TestLoginValid exists as a subtest inside TestLogin.

Steps

1. Confirm the nesting: find the parent test that calls t.Run("TestLoginValid", ...).

Expected: you know the parent name, for example TestLogin.

1. Run with the slash-separated path, quoting the pattern:

   go test ./auth -run 'TestLogin/TestLoginValid' -v

Expected: the subtest runs and -v shows === RUN TestLogin/TestLoginValid.

1. Anchor each level so similarly named tests do not sneak in (TestLogin also matches TestLoginExtra):

   go test ./auth -run '^TestLogin$/^TestLoginValid$' -v

Expected: only the exact parent and subtest run.

1. To run ALL subtests of a parent, end the pattern after the parent's slash:

   go test ./auth -run '^TestLogin$/' -v

Expected: every subtest under TestLogin runs.

When to use

• -run with a subtest name runs nothing.
• You want one subtest, not the whole parent.
• CI shards that select tests by name.

When not to use

• Top-level tests: plain -run '^TestLogin$' is enough.
• Table tests driven by a slice (not t.Run): filter inside the test or split them into subtests.
• Fuzz targets: use -fuzz, not -run.

Tool compatibility

• Go 1.22 through 1.24 go test; the -run slash-splitting behavior is long-standing and unchanged.

Variant phrasings

go test -run with slash pattern matches nothing

Each segment is matched against that level only; a typo in the parent segment silently matches zero parents. Print with -v to see what actually ran.

go test -run runs too many similarly named tests

Segments are unanchored regexes; add ^ and $ around each level.

Why it happens

-run splits the pattern on unescaped slashes and matches segment 1 against top-level test names, segment 2 against their subtests, and so on. A bare subtest name is compared against top-level names, matches nothing, and the subtests are never reached.

Edge cases

• Subtest names with spaces get sanitized (spaces become underscores); match the sanitized form.
• -run alone does not disable the test cache; add -count=1 if you suspect caching is hiding the skip.
• Regex metacharacters in test names (for example Test[0]) must be escaped in the pattern.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_GREq6x30-hJSPVShay3Umg