import { describe, it, expect, beforeEach, afterEach } from "@jest/globals";
import { promises as fs } from "fs";
import os from "os";
import path from "path";
import { setFrontmatter } from "../set_frontmatter.js";
import { setActiveTheme } from "../../themes/index.js";
describe("setFrontmatter", () => {
let tempDir: string;
beforeEach(async () => {
tempDir = await fs.mkdtemp(path.join(os.tmpdir(), "marp-frontmatter-"));
setActiveTheme("default");
});
afterEach(async () => {
await fs.rm(tempDir, { recursive: true, force: true });
});
it("creates the required frontmatter when missing", async () => {
const filePath = path.join(tempDir, "slides.md");
await fs.writeFile(filePath, "# Slide 1\n", "utf-8");
await setFrontmatter({ filePath });
const updated = await fs.readFile(filePath, "utf-8");
const expectedPrefix = [
"---",
"marp: true",
"theme: default",
'header: ""',
"paginate: false",
"---",
"",
].join("\n");
expect(updated.startsWith(expectedPrefix)).toBe(true);
expect(updated.trimEnd()).toContain("# Slide 1");
});
it("preserves existing header and paginate when values are omitted", async () => {
const filePath = path.join(tempDir, "existing.md");
const original = [
"---",
"marp: true",
"theme: uncover",
"header: Existing header",
"paginate: true",
"custom: keep-me",
"---",
"",
"# Slide",
].join("\n");
await fs.writeFile(filePath, original, "utf-8");
setActiveTheme("gaia");
await setFrontmatter({ filePath });
const updated = await fs.readFile(filePath, "utf-8");
expect(updated).toContain("theme: gaia");
expect(updated).toContain("header: Existing header");
expect(updated).toContain("paginate: true");
expect(updated).toContain("custom: keep-me");
});
it("overrides header and paginate when provided", async () => {
const filePath = path.join(tempDir, "override.md");
const original = [
"---",
"marp: true",
"theme: default",
"---",
"",
"# Slide",
].join("\n");
await fs.writeFile(filePath, original, "utf-8");
setActiveTheme("academic");
await setFrontmatter({
filePath,
header: "Kickoff: FY25",
paginate: true,
});
const updated = await fs.readFile(filePath, "utf-8");
expect(updated).toContain('header: "Kickoff: FY25"');
expect(updated).toContain("paginate: true");
expect(updated).toContain("theme: academic");
});
});
