test(fs): improve ensureSymlink() test

fs/ensure_symlink.ts

@@ -2,7 +2,7 @@
 import { dirname } from "@std/path/dirname";
 import { resolve } from "@std/path/resolve";
 import { ensureDir, ensureDirSync } from "./ensure_dir.ts";
-import { getFileInfoType } from "./_get_file_info_type.ts";
+import { getFileInfoType, type PathType } from "./_get_file_info_type.ts";
 import { toPathString } from "./_to_path_string.ts";
 
 const isWindows = Deno.build.os === "windows";
@@ -16,6 +16,12 @@ function resolveSymlinkTarget(target: string | URL, linkName: string | URL) {
   }
 }
 
+function getSymlinkOption(
+  type: PathType | undefined,
+): Deno.SymlinkOptions | undefined {
+  return isWindows ? { type: type === "dir" ? "dir" : "file" } : undefined;
+}
+
 /**
  * Asynchronously ensures that the link exists, and points to a valid file.
  *
@@ -51,11 +57,7 @@ export async function ensureSymlink(
 
   await ensureDir(dirname(toPathString(linkName)));
 
-  const options: Deno.SymlinkOptions | undefined = isWindows
-    ? {
-      type: srcFilePathType === "dir" ? "dir" : "file",
-    }
-    : undefined;
+  const options = getSymlinkOption(srcFilePathType);
 
   try {
     await Deno.symlink(target, linkName, options);
@@ -114,11 +116,7 @@ export function ensureSymlinkSync(
 
   ensureDirSync(dirname(toPathString(linkName)));
 
-  const options: Deno.SymlinkOptions | undefined = isWindows
-    ? {
-      type: srcFilePathType === "dir" ? "dir" : "file",
-    }
-    : undefined;
+  const options = getSymlinkOption(srcFilePathType);
 
   try {
     Deno.symlinkSync(target, linkName, options);

fs/ensure_symlink_test.ts

@@ -1,6 +1,6 @@
 // Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
 // TODO(axetroy): Add test for Windows once symlink is implemented for Windows.
-import { assertEquals, assertRejects, assertThrows } from "@std/assert";
+import { assert, assertEquals, assertRejects, assertThrows } from "@std/assert";
 import * as path from "@std/path";
 import { ensureSymlink, ensureSymlinkSync } from "./ensure_symlink.ts";
 
@@ -237,3 +237,71 @@ Deno.test("ensureSymlinkSync() creates symlink with relative target", function (
 
   Deno.removeSync(testDir, { recursive: true });
 });
+
+Deno.test("ensureSymlink() works with URLs", {
+  // TODO(kt3k): The 2nd test case doesn't pass on Windows. Fix it.
+  ignore: Deno.build.os === "windows",
+}, async () => {
+  const testDir = path.join(testdataDir, "link_file_with_url");
+  const testFile = path.join(testDir, "test.txt");
+  const linkFile = path.join(testDir, "link.txt");
+  {
+    try {
+      await Deno.mkdir(testDir, { recursive: true });
+      await Deno.writeFile(testFile, new Uint8Array());
+
+      await ensureSymlink(path.toFileUrl(testFile), path.toFileUrl(linkFile));
+
+      const srcStat = await Deno.lstat(testFile);
+      const linkStat = await Deno.lstat(linkFile);
+
+      assert(srcStat.isFile);
+      assert(linkStat.isSymlink);
+    } finally {
+      await Deno.remove(testDir, { recursive: true });
+    }
+  }
+
+  {
+    try {
+      await Deno.mkdir(testDir, { recursive: true });
+      await Deno.writeFile(testFile, new Uint8Array());
+
+      await ensureSymlink(testFile, path.toFileUrl(linkFile));
+
+      const srcStat = await Deno.lstat(testFile);
+      const linkStat = await Deno.lstat(linkFile);
+
+      assert(srcStat.isFile);
+      assert(linkStat.isSymlink);
+    } finally {
+      await Deno.remove(testDir, { recursive: true });
+    }
+  }
+});
+
+Deno.test(
+  "ensureSymlink() rejects with permission error if it doesn't have write permission",
+  { permissions: { read: true } },
+  async () => {
+    const testFile = path.join(testdataDir, "0.ts");
+    const linkFile = path.join(testdataDir, "link.ts");
+
+    await assertRejects(async () => {
+      await ensureSymlink(testFile, linkFile);
+    }, Deno.errors.PermissionDenied);
+  },
+);
+
+Deno.test(
+  "ensureSymlinkSync() throws permission error if it doesn't have write permission",
+  { permissions: { read: true } },
+  () => {
+    const testFile = path.join(testdataDir, "0.ts");
+    const linkFile = path.join(testdataDir, "link.ts");
+
+    assertThrows(() => {
+      ensureSymlinkSync(testFile, linkFile);
+    }, Deno.errors.PermissionDenied);
+  },
+);