test(ext/node): port _fs tests from std/node (#18262)

Co-authored-by: Yoshiya Hinosawa <stibium121@gmail.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/cli/tests/unit_node/_fs/_fs_exists_test.ts b/cli/tests/unit_node/_fs/_fs_exists_test.ts
new file mode 100644
index 000000000..9af5b3208
--- /dev/null
+++ b/cli/tests/unit_node/_fs/_fs_exists_test.ts
@@ -0,0 +1,65 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+import {
+  assert,
+  assertEquals,
+  assertStringIncludes,
+} from "../../../../test_util/std/testing/asserts.ts";
+import { exists, existsSync } from "node:fs";
+import { promisify } from "node:util";
+
+Deno.test("[std/node/fs] exists", async function () {
+  const availableFile = await new Promise((resolve) => {
+    const tmpFilePath = Deno.makeTempFileSync();
+    exists(tmpFilePath, (exists: boolean) => {
+      Deno.removeSync(tmpFilePath);
+      resolve(exists);
+    });
+  });
+  const notAvailableFile = await new Promise((resolve) => {
+    exists("./notAvailable.txt", (exists: boolean) => resolve(exists));
+  });
+  assertEquals(availableFile, true);
+  assertEquals(notAvailableFile, false);
+});
+
+Deno.test("[std/node/fs] existsSync", function () {
+  const tmpFilePath = Deno.makeTempFileSync();
+  assertEquals(existsSync(tmpFilePath), true);
+  Deno.removeSync(tmpFilePath);
+  assertEquals(existsSync("./notAvailable.txt"), false);
+});
+
+Deno.test("[std/node/fs] promisify(exists)", async () => {
+  const tmpFilePath = await Deno.makeTempFile();
+  try {
+    const existsPromisified = promisify(exists);
+    assert(await existsPromisified(tmpFilePath));
+    assert(!await existsPromisified("./notAvailable.txt"));
+  } finally {
+    await Deno.remove(tmpFilePath);
+  }
+});
+
+Deno.test("[std/node/fs] exists callback isn't called twice if error is thrown", async () => {
+  // This doesn't use `assertCallbackErrorUncaught()` because `exists()` doesn't return a standard node callback, which is what it expects.
+  const tempFile = await Deno.makeTempFile();
+  const importUrl = new URL("node:fs", import.meta.url);
+  const command = new Deno.Command(Deno.execPath(), {
+    args: [
+      "eval",
+      "--no-check",
+      `
+      import { exists } from ${JSON.stringify(importUrl)};
+
+      exists(${JSON.stringify(tempFile)}, (exists) => {
+        // If the bug is present and the callback is called again with false (meaning an error occurred),
+        // don't throw another error, so if the subprocess fails we know it had the correct behaviour.
+        if (exists) throw new Error("success");
+      });`,
+    ],
+  });
+  const { success, stderr } = await command.output();
+  await Deno.remove(tempFile);
+  assert(!success);
+  assertStringIncludes(new TextDecoder().decode(stderr), "Error: success");
+});