Preserve inline YAML document starts in aggregate reports

show_test.go

@@ -0,0 +1,47 @@
+package commandkit
+
+import (
+	"bytes"
+	"go.yaml.in/yaml/v4"
+	"io"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestEffectiveYAMLFramingPreservesOneNativeDocument(t *testing.T) {
+	for _, native := range []string{
+		"--- {setting: value}\n", "---\t{setting: value}\n", "--- value\n",
+		"--- |\n  first\n  second\n", "--- # authored\nsetting: value\n",
+		"setting: value\n", "%YAML 1.1\n--- {setting: value}\n",
+	} {
+		t.Run(native, func(t *testing.T) {
+			var want any
+			if err := yaml.Unmarshal([]byte(native), &want); err != nil {
+				t.Fatal(err)
+			}
+			framed := frameEffectiveYAML("app", []byte(native))
+			withoutLabel := bytes.Replace(framed, []byte("# scope: app\n"), nil, 1)
+			if !strings.HasPrefix(native, "---") && !strings.HasPrefix(native, "%") {
+				withoutLabel = bytes.TrimPrefix(withoutLabel, []byte("---\n"))
+			}
+			if !bytes.Equal(withoutLabel, []byte(native)) {
+				t.Fatalf("native content changed: %q", framed)
+			}
+			if !bytes.Contains(framed, []byte("# scope: app\n")) {
+				t.Fatalf("missing label: %q", framed)
+			}
+			decoder := yaml.NewDecoder(bytes.NewReader(framed))
+			var got any
+			if err := decoder.Decode(&got); err != nil {
+				t.Fatal(err)
+			}
+			if !reflect.DeepEqual(got, want) {
+				t.Fatalf("got=%#v want=%#v", got, want)
+			}
+			if err := decoder.Decode(new(any)); err != io.EOF {
+				t.Fatalf("extra document: %v", err)
+			}
+		})
+	}
+}