Add tests for returned promises by node:fs/promises

test/js/node/fs/fs-promises-returns-promise.test.ts

@@ -0,0 +1,188 @@
+import { describe, expect, it } from "bun:test";
+import { tempDirWithFiles } from "harness";
+import * as promises from "node:fs/promises";
+import path from "node:path";
+
+describe("fs.promises functions return proper Promise instances", () => {
+  it("should return Promise instances for asyncWrap functions", async () => {
+    const dir = tempDirWithFiles("fs-promises-test", {
+      "test.txt": "hello world",
+      "another.txt": "test content",
+    });
+
+    const testFile = path.join(dir, "test.txt");
+    const nonExistentFile = path.join(dir, "nonexistent.txt");
+    const tempFile = path.join(dir, "temp.txt");
+
+    // Test functions that use asyncWrap and should return proper Promise instances
+    const tests = [
+      // File operations
+      { name: "readFile", fn: () => promises.readFile(testFile) },
+      { name: "writeFile", fn: () => promises.writeFile(tempFile, "new content") },
+      { name: "appendFile", fn: () => promises.appendFile(testFile, " appended") },
+      { name: "access", fn: () => promises.access(testFile) },
+      { name: "stat", fn: () => promises.stat(testFile) },
+      { name: "lstat", fn: () => promises.lstat(testFile) },
+
+      // Directory operations
+      { name: "readdir", fn: () => promises.readdir(dir) },
+      { name: "mkdir", fn: () => promises.mkdir(path.join(dir, "new-dir")) },
+
+      // File manipulation
+      { name: "copyFile", fn: () => promises.copyFile(testFile, path.join(dir, "copy.txt")) },
+      { name: "rename", fn: () => promises.rename(path.join(dir, "copy.txt"), path.join(dir, "renamed.txt")) },
+      { name: "truncate", fn: () => promises.truncate(testFile, 5) },
+      { name: "unlink", fn: () => promises.unlink(path.join(dir, "renamed.txt")) },
+
+      // Operations that may fail but should still return Promise
+      { name: "rm", fn: () => promises.rm(nonExistentFile), shouldFail: true },
+      { name: "rmdir", fn: () => promises.rmdir(nonExistentFile), shouldFail: true },
+      { name: "readlink", fn: () => promises.readlink(testFile), shouldFail: true }, // Not a symlink
+    ];
+
+    for (const test of tests) {
+      try {
+        const result = test.fn();
+
+        // Check that the result is a Promise instance
+        expect(result instanceof Promise).toBe(true);
+        expect(typeof result.then).toBe("function");
+        expect(typeof result.catch).toBe("function");
+        expect(typeof result.finally).toBe("function");
+        expect(result.constructor.name).toBe("Promise");
+
+        // Actually await the promise to ensure it works
+        if (test.shouldFail) {
+          await expect(result).rejects.toThrow();
+        } else {
+          await result;
+        }
+      } catch (error) {
+        throw new Error(`Test for ${test.name} failed: ${error}`);
+      }
+    }
+  });
+
+  it("should return Promise for open() which creates FileHandle", async () => {
+    const dir = tempDirWithFiles("fs-promises-open-test", {
+      "test.txt": "hello world",
+    });
+
+    const testFile = path.join(dir, "test.txt");
+    const openResult = promises.open(testFile, "r");
+
+    expect(openResult instanceof Promise).toBe(true);
+    expect(typeof openResult.then).toBe("function");
+    expect(openResult.constructor.name).toBe("Promise");
+
+    // Test that it resolves to a FileHandle
+    const fileHandle = await openResult;
+    expect(typeof fileHandle.close).toBe("function");
+    expect(typeof fileHandle.read).toBe("function");
+    expect(typeof fileHandle.write).toBe("function");
+
+    await fileHandle.close();
+  });
+
+  it("should return Promise for exists() function", async () => {
+    const dir = tempDirWithFiles("fs-promises-exists-test", {
+      "exists.txt": "I exist",
+    });
+
+    const existingFile = path.join(dir, "exists.txt");
+    const nonExistentFile = path.join(dir, "does-not-exist.txt");
+
+    // Test with existing file
+    const existsResult1 = promises.exists(existingFile);
+    expect(existsResult1 instanceof Promise).toBe(true);
+    expect(existsResult1.constructor.name).toBe("Promise");
+    expect(await existsResult1).toBe(true);
+
+    // Test with non-existent file
+    const existsResult2 = promises.exists(nonExistentFile);
+    expect(existsResult2 instanceof Promise).toBe(true);
+    expect(existsResult2.constructor.name).toBe("Promise");
+    expect(await existsResult2).toBe(false);
+  });
+
+  it("should return Promise for functions with file descriptor operations", async () => {
+    const dir = tempDirWithFiles("fs-promises-fd-test", {
+      "test.txt": "hello world for fd test",
+    });
+
+    const testFile = path.join(dir, "test.txt");
+    const fileHandle = await promises.open(testFile, "r+");
+
+    try {
+      // Test fd-based operations that use asyncWrap
+      const fdTests = [
+        { name: "fstat", fn: () => promises.fstat(fileHandle.fd) },
+        { name: "fchmod", fn: () => promises.fchmod(fileHandle.fd, 0o644) },
+        { name: "fchown", fn: () => promises.fchown(fileHandle.fd, process.getuid?.() ?? 0, process.getgid?.() ?? 0) },
+        { name: "fsync", fn: () => promises.fsync(fileHandle.fd) },
+        { name: "fdatasync", fn: () => promises.fdatasync(fileHandle.fd) },
+        { name: "ftruncate", fn: () => promises.ftruncate(fileHandle.fd, 5) },
+      ];
+
+      for (const test of fdTests) {
+        try {
+          const result = test.fn();
+          expect(result instanceof Promise).toBe(true);
+          expect(result.constructor.name).toBe("Promise");
+          await result;
+        } catch (error) {
+          // Some operations might fail due to permissions, but should still return Promise
+          console.warn(`${test.name} failed (expected on some systems): ${error}`);
+        }
+      }
+    } finally {
+      await fileHandle.close();
+    }
+  });
+
+  it("regression test: fs.promises.rm should return Promise instance, not InternalPromise", async () => {
+    // This is the specific bug that was fixed - rm was returning InternalPromise instead of Promise
+    const nonExistentFile = path.join(__dirname, "definitely-does-not-exist-" + Math.random());
+
+    const rmResult = promises.rm(nonExistentFile);
+
+    // The main assertion - this was returning false before the fix
+    expect(rmResult instanceof Promise).toBe(true);
+    expect(rmResult.constructor.name).toBe("Promise");
+    expect(typeof rmResult.then).toBe("function");
+    expect(typeof rmResult.catch).toBe("function");
+    expect(typeof rmResult.finally).toBe("function");
+
+    // Should reject with ENOENT error
+    await expect(rmResult).rejects.toThrow();
+  });
+
+  it("should have correct function names without exposing internal implementation", () => {
+    // Ensure function names don't leak internal implementation details
+    expect(promises.rm.name).toBe("rm");
+    expect(promises.readFile.name).toBe("readFile");
+    expect(promises.writeFile.name).toBe("writeFile");
+    expect(promises.appendFile.name).toBe("appendFile");
+    expect(promises.exists.name).toBe("exists");
+    expect(promises.open.name).toBe("open");
+    expect(promises.access.name).toBe("access");
+    expect(promises.stat.name).toBe("stat");
+    expect(promises.readdir.name).toBe("readdir");
+    expect(promises.mkdir.name).toBe("mkdir");
+    expect(promises.copyFile.name).toBe("copyFile");
+    expect(promises.rename.name).toBe("rename");
+    expect(promises.unlink.name).toBe("unlink");
+    expect(promises.truncate.name).toBe("truncate");
+    expect(promises.chmod.name).toBe("chmod");
+    expect(promises.chown.name).toBe("chown");
+
+    // Ensure no function names start with "defaultAsync" which would expose internal implementation
+    const functionNames = Object.getOwnPropertyNames(promises)
+      .filter(name => typeof promises[name] === "function")
+      .map(name => promises[name].name);
+
+    for (const name of functionNames) {
+      expect(name).not.toMatch(/^defaultAsync/);
+    }
+  });
+});