test: gate go-libraries integration tests behind -tags=integration

Assisted-by: GLM 5.2

format/format_test.go

@@ -5,7 +5,6 @@ package format
 
 import (
 	"os"
-	"path/filepath"
 	"strings"
 	"testing"
 
@@ -172,11 +171,9 @@ func TestIdempotent(t *testing.T) {
 }
 
 // TestRoundTrip checks that formatting produces source that still parses
-// cleanly, on the fixture and on the real go-flac kernels when present.
+// cleanly on the in-repository fixture.
 func TestRoundTrip(t *testing.T) {
 	files := []string{"../testdata/sample_amd64.s"}
-	real, _ := filepath.Glob("../../go-libraries/go-*/*.s")
-	files = append(files, real...)
 	for _, path := range files {
 		src, err := os.ReadFile(path)
 		if err != nil {

format/integration_test.go

@@ -0,0 +1,40 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build integration
+
+// Package format integration tests against the production go-libraries kernels.
+// Excluded from the default test run so coverage is identical locally and in CI.
+// Run explicitly with:  go test -tags=integration ./format/
+package format
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"sourcedock.dev/petrbalvin/gasm-devkit/parser"
+)
+
+// TestRoundTripRealGoLibraries checks that formatting the production kernels
+// still produces source that parses cleanly.
+func TestRoundTripRealGoLibraries(t *testing.T) {
+	real, _ := filepath.Glob("../../go-libraries/go-*/*.s")
+	if len(real) == 0 {
+		t.Skip("go-libraries repository not present")
+	}
+	for _, path := range real {
+		src, err := os.ReadFile(path)
+		if err != nil {
+			t.Fatal(err)
+		}
+		formatted := Source(path, string(src))
+		if _, errs := parser.Parse(path, formatted); len(errs) > 0 {
+			t.Errorf("formatted %s no longer parses: %v", path, errs)
+		}
+		if strings.TrimSpace(formatted) == "" {
+			t.Errorf("formatted %s is empty", path)
+		}
+	}
+}