internal/tdtest: mimic replacement of testing.Run in Select

This allows the select string to be the same as the subtest name.

This is only an approximation, as testing.T.Run does more
rewriting.

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: I36290242264d831b788fe9a5975210f5c1e4ba41
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1167817
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

internal/tdtest/tdtest.go

@@ -40,9 +40,6 @@ import (
 // - make name field explicit, i.e. Name("name"), field tag, or tdtest.Name type.
 // - allow "skip" field. Again either SkipName("skip"), tag, or Skip type.
 // - allow for tdtest:"noupdate" field tag.
-// - should we derive names from field names? This would require always
-//   loading the packages data upon error. Could be an option to disable, or
-//   implicitly it would only be loaded if there is an error without message.
 // - Option: allow ignore field that lists a set of fields to not be tested
 //   for that particular test case: ignore: tdtest.Ignore("want1", "want2")
 //
@@ -165,6 +162,7 @@ func (t *T) Select(tests ...any) {
 				return
 			}
 		case string:
+			n = strings.ReplaceAll(n, " ", "_")
 			if n == parts[len(parts)-1] {
 				return
 			}