fix CI: skip metadata tests when test_data is absent, use fmt.Fprintf in genevents

backend/events/cmd/genevents/main.go

@@ -134,7 +134,7 @@ func generateTypeScript(groups []constGroup) string {
 		}
 
 		for _, c := range g.Consts {
-			b.WriteString(fmt.Sprintf("    %s: %q,\n", c.Name, c.Value))
+			fmt.Fprintf(&b, "    %s: %q,\n", c.Name, c.Value)
 		}
 		// Blank line between groups, but not after the last one.
 		if i < len(groups)-1 {

backend/metadata/flacduration_test.go

@@ -13,6 +13,10 @@ func testFlacFiles(t *testing.T) []string {
 
 	root := filepath.Join("..", "..", "test_data")
 
+	if _, err := os.Stat(root); os.IsNotExist(err) {
+		t.Skip("test_data directory not present, skipping")
+	}
+
 	var files []string
 
 	err := filepath.Walk(root, func(

backend/metadata/mp3duration_test.go

@@ -13,6 +13,10 @@ func testMP3Files(t *testing.T) []string {
 
 	root := filepath.Join("..", "..", "test_data")
 
+	if _, err := os.Stat(root); os.IsNotExist(err) {
+		t.Skip("test_data directory not present, skipping")
+	}
+
 	var files []string
 
 	err := filepath.Walk(root, func(