Add required-flags render CLI coverage

internal/cli/render_test.go

@@ -68,6 +68,38 @@ func TestRenderEndToEndMarkdownOutput(t *testing.T) {
 	}
 }
 
+func TestRenderWorksWithRequiredFlagsOnly(t *testing.T) {
+	dir := t.TempDir()
+	input := writeJSONFile(t, dir, "input.json", `{
+		"metadata": {
+			"application": "seriatim",
+			"version": "v-test",
+			"output_schema": "seriatim-minimal"
+		},
+		"segments": [
+			{"id": 1, "start": 1, "end": 2, "speaker": "Eric", "text": "Hello there."}
+		]
+	}`)
+	output := writeJSONFile(t, dir, "output.md", "")
+
+	err := executeRender(
+		"--input-file", input,
+		"--output-file", output,
+		"--format", config.RenderFormatMarkdown,
+	)
+	if err != nil {
+		t.Fatalf("render with required flags failed: %v", err)
+	}
+
+	data := readFile(t, output)
+	if !strings.Contains(data, "# Transcript") {
+		t.Fatalf("missing default title:\n%s", data)
+	}
+	if !strings.Contains(data, "[00:00:01–00:00:02] **Eric:** Hello there.") {
+		t.Fatalf("missing rendered segment:\n%s", data)
+	}
+}
+
 func TestRenderRejectsUnsupportedFormat(t *testing.T) {
 	dir := t.TempDir()
 	input := writeJSONFile(t, dir, "input.json", `{"metadata":{"application":"seriatim","version":"v-test","output_schema":"seriatim-minimal"},"segments":[]}`)