feat(test): add test utils (#12)

* feat(test-utils): add test utils

* chore: add changeset

Author: natemoo-re

.changeset/old-mugs-stare.md

@@ -0,0 +1,5 @@
+---
+"@bomb.sh/tools": patch
+---
+
+Adds `@bomb.sh/tools/test-utils` export with `createFixture()`

package.json

@@ -26,6 +26,10 @@
     ".": {
       "import": "./dist/bin.mjs"
     },
+    "./test-utils": {
+      "types": "./dist/test-utils.d.mts",
+      "import": "./dist/test-utils.mjs"
+    },
     "./*": "./dist/*",
     "./package.json": "./package.json",
     "./tsconfig.json": "./tsconfig.json"

src/test-utils.test.ts

@@ -0,0 +1,43 @@
+import { describe, it, expect } from "vitest";
+import { existsSync } from "node:fs";
+import { readFile, writeFile } from "node:fs/promises";
+import { createFixture } from "./test-utils.ts";
+
+describe("createFixture", () => {
+  it("creates files on disk from inline tree", async () => {
+    const fixture = await createFixture({
+      "hello.txt": "hello world",
+    });
+    const content = await readFile(fixture.resolve("hello.txt"), "utf8");
+    expect(content).toBe("hello world");
+  });
+
+  it("creates nested directories from slash-separated keys", async () => {
+    const fixture = await createFixture({
+      "src/index.ts": "export const x = 1",
+      "src/utils/helpers.ts": "export function help() {}",
+    });
+    expect(existsSync(fixture.resolve("src/index.ts"))).toBe(true);
+    expect(existsSync(fixture.resolve("src/utils/helpers.ts"))).toBe(true);
+  });
+
+  it("resolve returns absolute path within fixture root", async () => {
+    const fixture = await createFixture({ "a.txt": "" });
+    expect(fixture.resolve("a.txt").toString()).toContain(fixture.root.toString());
+  });
+
+  it("readFile reads the actual file", async () => {
+    const fixture = await createFixture({ "a.txt": "Empty" });
+    expect(await fixture.readFile("a.txt")).toEqual("Empty");
+    await writeFile(fixture.resolve("a.txt"), "Hello world!", { encoding: "utf-8" });
+    expect(await fixture.readFile("a.txt")).toEqual("Hello world!");
+  });
+
+  it("cleanup removes the temp directory", async () => {
+    const fixture = await createFixture({ "a.txt": "" });
+    const path = fixture.root;
+    expect(existsSync(path)).toBe(true);
+    await fixture.cleanup();
+    expect(existsSync(path)).toBe(false);
+  });
+});

src/test-utils.ts

@@ -0,0 +1,40 @@
+import type { PathLike } from "node:fs";
+import { mkdtemp, mkdir, writeFile, rm, readFile as fsReadFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { sep } from "node:path";
+import { fileURLToPath, pathToFileURL } from "node:url";
+import { onTestFinished } from "vitest";
+
+export interface Fixture {
+  root: URL;
+  resolve: (...segments: string[]) => URL;
+  readFile: (file: PathLike) => Promise<string>;
+  cleanup: () => Promise<void>;
+}
+
+export async function createFixture(files: Record<string, string>): Promise<Fixture> {
+  const root = new URL(`bsh-`, `file://${tmpdir()}/`);
+  const path = await mkdtemp(fileURLToPath(root));
+  const base = pathToFileURL(path + sep);
+
+  for (const [name, content] of Object.entries(files)) {
+    const url = new URL(name, base);
+    const dir = new URL("./", url);
+    await mkdir(dir, { recursive: true });
+    await writeFile(url, content, "utf8");
+  }
+
+  const cleanup = () => rm(path, { recursive: true, force: true });
+  onTestFinished(cleanup);
+
+  const resolve = (...segments: string[]) => new URL(`./${segments.join("/")}`, base);
+  const readFile = (file: PathLike) =>
+    fsReadFile(new URL(`./${file}`, base), { encoding: "utf-8" });
+
+  return {
+    root: pathToFileURL(path),
+    resolve,
+    readFile,
+    cleanup,
+  };
+}