feat(fs): mock stubs current working directory by default

README.md

@@ -157,6 +157,14 @@ assert(Deno.readTextFile !== original.readTextFile);
 assert(Deno.readTextFileSync !== original.readTextFileSync);
 ```
 
+Stub the current working directory by default:
+
+```typescript
+fs.mock();
+await fs.use(() => Deno.writeTextFile("./test.txt", "amber"));
+assertRejects(() => Deno.readTextFile("./test.txt"));
+```
+
 #### `use`
 
 Replace file system functions within the callback:
@@ -188,6 +196,14 @@ assertSpyCalls(cwd.readTextFile, 1);
 assertSpyCalls(src.readTextFile, 0);
 ```
 
+Accept a URL:
+
+```typescript
+const spy = fs.spy(new URL("..", import.meta.url));
+await fs.use(() => Deno.readTextFile("./README.md"));
+assertSpyCalls(spy.readTextFile, 1);
+```
+
 #### `stub`
 
 Not write to the original path:

src/fs.ts

@@ -5,10 +5,10 @@
  */
 
 import { mapValues, pick } from "@std/collections";
-import { join } from "@std/path";
+import { dirname, fromFileUrl, join, resolve } from "@std/path";
 import type { Spy } from "@std/testing/mock";
 import * as std from "@std/testing/mock";
-import { isUnder, relative, tryCatch, tryFinally } from "./internal.ts";
+import { relative, tryCatch, tryFinally } from "./internal.ts";
 
 /**
  * The base names of Deno's APIs related to file system operations that takes
@@ -117,7 +117,7 @@ export interface FileSystemStub extends FileSystemSpy {
  * to a temporary directory.
  */
 function createFsFake(
-  base: string | URL,
+  base: string,
   temp: string,
   readThrough: boolean,
 ): Fs {
@@ -156,12 +156,16 @@ function createFsFake(
  */
 const spies = new class extends Map<string | URL, FileSystemSpy> {
   /** Returns the spy for the path that is under the given path. */
-  override get(key: string | URL) {
-    for (const [path, spy] of this) {
-      if (isUnder(key, path)) {
-        return spy;
-      }
+  override get(path: string | URL): FileSystemSpy | undefined {
+    const spy = super.get(path);
+    if (spy) {
+      return spy;
+    }
+    path = path.toString();
+    if (path === "." || path === ".." || path === "/") {
+      return;
     }
+    return this.get(dirname(path));
   }
 }();
 
@@ -193,6 +197,7 @@ export function stub(
   path: string | URL,
   fakeOrOptions?: Partial<Fs> | StubOptions,
 ): FileSystemStub {
+  path = normalize(path);
   const temp = Deno.makeTempDirSync();
 
   const fake = isStubOptions(fakeOrOptions)
@@ -221,9 +226,10 @@ export function spy(
 }
 
 export function mock(): Disposable {
-  for (const name of FsFnNames) {
-    mockFsFn(name);
+  if (spies.size === 0) {
+    stub(Deno.cwd());
   }
+  FsFnNames.forEach((name) => mockFsFn(name));
   return {
     [Symbol.dispose]() {
       dispose();
@@ -234,7 +240,8 @@ export function mock(): Disposable {
 function mockFsFn<T extends FsFnName>(name: T) {
   Deno[name] = new Proxy(Deno[name], {
     apply(target, thisArg, args) {
-      const spy = spies.get(args[0])?.[name];
+      const path = normalize(args[0]);
+      const spy = spies.get(path)?.[name];
       if (spy) {
         return Reflect.apply(spy, thisArg, args);
       }
@@ -249,9 +256,7 @@ export function use<T>(fn: () => T): T {
 }
 
 export function restore() {
-  for (const name of FsFnNames) {
-    restoreFsFn(name, fs[name]);
-  }
+  FsFnNames.forEach((name) => restoreFsFn(name, fs[name]));
 }
 
 export function dispose() {
@@ -265,3 +270,13 @@ function restoreFsFn<T extends FsFnName>(
 ) {
   Deno[name] = fn;
 }
+
+/** Normalize a path or file URL to an absolute path */
+function normalize(path: string | URL): string {
+  if (path instanceof URL) {
+    path = path.protocol === "file:" ? fromFileUrl(path) : path.href;
+  } else {
+    path = resolve(path);
+  }
+  return path.endsWith("/") ? path.slice(0, -1) : path;
+}

src/fs_test.ts

@@ -1,14 +1,12 @@
-import { assert, assertEquals, assertThrows } from "@std/assert";
+import { assert, assertEquals, assertRejects, assertThrows } from "@std/assert";
 import { afterAll, afterEach, beforeAll, describe, it } from "@std/testing/bdd";
 import { assertSpyCalls } from "@std/testing/mock";
 import * as fs from "./fs.ts";
 
 describe("mock", () => {
   const original = { ...Deno };
 
-  afterEach(() => {
-    fs.restore();
-  });
+  afterEach(() => fs.dispose());
 
   it("should return a disposable", () => {
     assert(Symbol.dispose in fs.mock());
@@ -19,11 +17,19 @@ describe("mock", () => {
     assert(Deno.readTextFile !== original.readTextFile);
     assert(Deno.readTextFileSync !== original.readTextFileSync);
   });
+
+  it("should stub the current working directory by default", async () => {
+    fs.mock();
+    await fs.use(() => Deno.writeTextFile("./test.txt", "amber"));
+    assertRejects(() => Deno.readTextFile("./test.txt"));
+  });
 });
 
 describe("use", () => {
   const original = { ...Deno };
 
+  afterEach(() => fs.dispose());
+
   it("should replace file system functions within the callback", () => {
     fs.use(() => {
       assert(Deno.readTextFile !== original.readTextFile);
@@ -33,14 +39,10 @@ describe("use", () => {
 });
 
 describe("spy", () => {
-  let cwd: string;
-
   beforeAll(() => {
-    cwd = Deno.cwd();
     Deno.chdir(new URL("../", import.meta.url));
   });
   afterEach(() => fs.dispose());
-  afterAll(() => Deno.chdir(cwd));
 
   it("should spy file system functions", async () => {
     const spy = fs.spy(".");
@@ -55,6 +57,12 @@ describe("spy", () => {
     assertSpyCalls(cwd.readTextFile, 1);
     assertSpyCalls(src.readTextFile, 0);
   });
+
+  it("should accept a URL", async () => {
+    const spy = fs.spy(new URL("..", import.meta.url));
+    await fs.use(() => Deno.readTextFile("./README.md"));
+    assertSpyCalls(spy.readTextFile, 1);
+  });
 });
 
 describe("stub", () => {
@@ -117,6 +125,7 @@ describe("restore", () => {
     cwd = Deno.cwd();
     Deno.chdir(new URL("../", import.meta.url));
   });
+  afterEach(() => fs.dispose());
   afterAll(() => Deno.chdir(cwd));
 
   it("should restore file system functions", () => {

src/internal.ts

@@ -1,16 +1,6 @@
 import { toPath } from "@molt/lib/path";
 import * as std from "@std/path";
 
-/**
- * Check if a path is under a base path.
- */
-export function isUnder(
-  path: string | URL,
-  base: string | URL,
-): boolean {
-  return toPath(path).startsWith(toPath(base));
-}
-
 /**
  * Return the relative path from the first path to the second path.
  */

src/internal_test.ts

@@ -1,6 +1,6 @@
-import { assert, assertEquals, assertFalse } from "@std/assert";
+import { assert, assertEquals } from "@std/assert";
 import { afterAll, beforeAll, describe, it } from "@std/testing/bdd";
-import { isUnder, relative, tryCatchFinally } from "./internal.ts";
+import { relative, tryCatchFinally } from "./internal.ts";
 
 describe("tryCatchFinally", () => {
   it("should execute the function and return the result", () => {
@@ -122,70 +122,3 @@ describe("relative", () => {
     );
   });
 });
-
-describe("isUnder", () => {
-  let cwd: string;
-
-  beforeAll(() => {
-    cwd = Deno.cwd();
-    Deno.chdir(new URL(".", import.meta.url));
-  });
-
-  afterAll(() => {
-    Deno.chdir(cwd);
-  });
-
-  it("should return true if the first path is under the second path", () => {
-    assert(
-      isUnder(
-        new URL("../README.md", import.meta.url),
-        new URL("..", import.meta.url),
-      ),
-    );
-    assert(
-      isUnder(
-        "../README.md",
-        "..",
-      ),
-    );
-    assert(
-      isUnder(
-        "../README.md",
-        new URL("..", import.meta.url),
-      ),
-    );
-    assert(
-      isUnder(
-        new URL("../README.md", import.meta.url),
-        "..",
-      ),
-    );
-  });
-
-  it("should return false if the first path is not under the second path", () => {
-    assertFalse(
-      isUnder(
-        new URL("../README.md", import.meta.url),
-        new URL(".", import.meta.url),
-      ),
-    );
-    assertFalse(
-      isUnder(
-        "../README.md",
-        ".",
-      ),
-    );
-    assertFalse(
-      isUnder(
-        "../README.md",
-        new URL(".", import.meta.url),
-      ),
-    );
-    assert(
-      isUnder(
-        new URL("../README.md", import.meta.url),
-        "..",
-      ),
-    );
-  });
-});