Summary

Fixes #20047.

In cli/js/40_test.js, testInner now checks whether the registered test function carries a Symbol.for("Deno.test.location") property before falling back to core.currentUserCallSite(). If the symbol is set, its string value (format: "fileName:lineNumber:columnNumber") is parsed and used as the test location. This allows test-helper libraries like @std/testing/bdd to declare the user's source location instead of the library's own call site.

Root Cause

In cli/js/40_test.js:302 (before this fix):

testDesc.location = core.currentUserCallSite();

core.currentUserCallSite() captures the stack frame where Deno.test() is called. When a BDD library such as @std/testing/bdd wraps user tests and calls Deno.test() internally, the captured location is inside the library file (e.g. https://jsr.io/@std/testing/.../bdd.ts), not the user's test file.

The JUnit reporter uses description.location.file_name to both name the <testsuite> element and populate each <testcase classname="...">. With the wrong location, every test registered via bdd.ts is grouped under the library URL:

<!-- Before fix -->
<testsuite name="https://jsr.io/@std/testing/1.0.0/bdd.ts" ...>

This breaks CI test-reporting tools (e.g. dorny/test-reporter, EnricoMi/publish-unit-test-result-action) that rely on the suite name to map results back to source files.

Solution

Before reading core.currentUserCallSite(), check for a well-known symbol on the test function:

const locationOverride = testDesc.fn[SymbolFor("Deno.test.location")];
testDesc.location = locationOverride
  ? parseTestLocation(locationOverride)
  : core.currentUserCallSite();

parseTestLocation splits "fileName:lineNumber:columnNumber" from the right, so URL schemes containing : (e.g. file:///…, https://…) are handled correctly.

A follow-up change to @std/testing/bdd (in the std repo) will set Symbol.for("Deno.test.location") on each wrapped test function to point at the user's source file, completing the fix end-to-end.

Testing

• Added tests/specs/test/junit_location_override/ — a new spec test that simulates a library-registered test (by setting Symbol.for("Deno.test.location") on the function) alongside an ordinary test, and asserts that the JUnit XML groups them into separate <testsuite> elements with the correct names and line/column numbers.
• All six existing JUnit spec tests continue to pass unchanged.

test specs::test::hide_stacktraces::reporter_junit ... ok
test specs::test::junit                           ... ok
test specs::test::junit_console_formatting        ... ok
test specs::test::junit_location_override         ... ok  ← new
test specs::test::junit_multiple_test_files       ... ok
test specs::test::junit_nested                    ... ok

Checklist

• Fixes the root cause (not just the symptom) — the location is captured correctly at registration time
• New spec test covers the exact scenario from the issue report
• All existing JUnit spec tests pass
• No unrelated changes
• Code style matches surrounding primordials pattern (StringPrototypeLastIndexOf, StringPrototypeSlice, SymbolFor)
• Read CONTRIBUTING.md and followed its requirements