[release-branch.go1.22] internal/testenv: support the LUCI mobile builders in tests

This change updates the testenv tests to correctly match on future LUCI
builder names for mobile builders. This isn't a problem today because
those haven't been set up yet, but the builder names are structured and
it's clear where the modifiers will appear. Might as well set them up
now.

For golang#65473.
Fixes golang#65474.

Change-Id: I244b88a62a90312c0f3ff2360527d58531070362
Reviewed-on: https://go-review.googlesource.com/c/go/+/558597
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
(cherry picked from commit 5c7c24c)
Reviewed-on: https://go-review.googlesource.com/c/go/+/560536

Author: mknyszek

src/internal/testenv/testenv_test.go

@@ -78,7 +78,7 @@ func TestHasGoBuild(t *testing.T) {
 		// we will presumably find out about it when those tests fail.)
 		switch runtime.GOOS {
 		case "ios":
-			if strings.HasSuffix(b, "-corellium") {
+			if isCorelliumBuilder(b) {
 				// The corellium environment is self-hosting, so it should be able
 				// to build even though real "ios" devices can't exec.
 			} else {
@@ -89,7 +89,7 @@ func TestHasGoBuild(t *testing.T) {
 				return
 			}
 		case "android":
-			if strings.HasSuffix(b, "-emu") && platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, false) {
+			if isEmulatedBuilder(b) && platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, false) {
 				// As of 2023-05-02, the test environment on the emulated builders is
 				// missing a C linker.
 				t.Logf("HasGoBuild is false on %s", b)
@@ -153,7 +153,7 @@ func TestMustHaveExec(t *testing.T) {
 			t.Errorf("expected MustHaveExec to skip on %v", runtime.GOOS)
 		}
 	case "ios":
-		if b := testenv.Builder(); strings.HasSuffix(b, "-corellium") && !hasExec {
+		if b := testenv.Builder(); isCorelliumBuilder(b) && !hasExec {
 			// Most ios environments can't exec, but the corellium builder can.
 			t.Errorf("expected MustHaveExec not to skip on %v", b)
 		}
@@ -186,3 +186,23 @@ func TestCleanCmdEnvPWD(t *testing.T) {
 	}
 	t.Error("PWD not set in cmd.Env")
 }
+
+func isCorelliumBuilder(builderName string) bool {
+	// Support both the old infra's builder names and the LUCI builder names.
+	// The former's names are ad-hoc so we could maintain this invariant on
+	// the builder side. The latter's names are structured, and "corellium" will
+	// appear as a "host" suffix after the GOOS and GOARCH, which always begin
+	// with an underscore.
+	return strings.HasSuffix(builderName, "-corellium") || strings.Contains(builderName, "_corellium")
+}
+
+func isEmulatedBuilder(builderName string) bool {
+	// Support both the old infra's builder names and the LUCI builder names.
+	// The former's names are ad-hoc so we could maintain this invariant on
+	// the builder side. The latter's names are structured, and the signifier
+	// of emulation "emu" will appear as a "host" suffix after the GOOS and
+	// GOARCH because it modifies the run environment in such a way that it
+	// the target GOOS and GOARCH may not match the host. This suffix always
+	// begins with an underscore.
+	return strings.HasSuffix(builderName, "-emu") || strings.Contains(builderName, "_emu")
+}