expand shim coverage, additional fs shims, add light stream shim

packages/shim/src/node/assert.js

@@ -0,0 +1,82 @@
+class AssertionError extends Error {
+  constructor(message) {
+    super(message || "Assertion failed");
+    this.name = "AssertionError";
+  }
+}
+
+function assert(value, message) {
+  if (!value) {
+    throw new AssertionError(message);
+  }
+}
+
+assert.AssertionError = AssertionError;
+assert.ok = assert;
+assert.strict = assert;
+
+assert.fail = function (message) {
+  throw new AssertionError(message || "Failed");
+};
+
+assert.equal = function (actual, expected, message) {
+  if (actual != expected) {
+    throw new AssertionError(message || `${actual} == ${expected}`);
+  }
+};
+
+assert.notEqual = function (actual, expected, message) {
+  if (actual == expected) {
+    throw new AssertionError(message || `${actual} != ${expected}`);
+  }
+};
+
+assert.strictEqual = function (actual, expected, message) {
+  if (actual !== expected) {
+    throw new AssertionError(message || `${actual} === ${expected}`);
+  }
+};
+
+assert.notStrictEqual = function (actual, expected, message) {
+  if (actual === expected) {
+    throw new AssertionError(message || `${actual} !== ${expected}`);
+  }
+};
+
+assert.deepEqual = function (actual, expected, message) {
+  if (JSON.stringify(actual) !== JSON.stringify(expected)) {
+    throw new AssertionError(message || "deepEqual");
+  }
+};
+
+assert.deepStrictEqual = assert.deepEqual;
+
+assert.throws = function (fn, message) {
+  let threw = false;
+
+  try {
+    fn();
+  } catch {
+    threw = true;
+  }
+
+  if (!threw) {
+    throw new AssertionError(message || "Missing expected exception");
+  }
+};
+
+assert.doesNotThrow = function (fn, message) {
+  try {
+    fn();
+  } catch (e) {
+    throw new AssertionError(message || `Got unwanted exception: ${e.message}`);
+  }
+};
+
+assert.ifError = function (value) {
+  if (value) {
+    throw new AssertionError(`ifError got unwanted exception: ${value}`);
+  }
+};
+
+export const assertShim = assert;

packages/shim/src/node/assert.test.js

@@ -0,0 +1,30 @@
+import { describe, it, expect } from "vitest";
+import { assertShim as assert } from "./assert.js";
+
+describe("assert shim", () => {
+  it("is callable and throws on a falsy value", () => {
+    expect(() => assert(false)).toThrow();
+    expect(() => assert(true)).not.toThrow();
+  });
+
+  it("equal throws on mismatch and passes on loose match", () => {
+    expect(() => assert.equal(1, 2)).toThrow();
+    expect(() => assert.equal(1, 1)).not.toThrow();
+    expect(() => assert.equal(1, "1")).not.toThrow();
+  });
+
+  it("strictEqual distinguishes type", () => {
+    expect(() => assert.strictEqual(1, "1")).toThrow();
+    expect(() => assert.strictEqual(1, 1)).not.toThrow();
+  });
+
+  it("throws() verifies that a function threw", () => {
+    expect(() =>
+      assert.throws(() => {
+        throw new Error("x");
+      }),
+    ).not.toThrow();
+
+    expect(() => assert.throws(() => {})).toThrow();
+  });
+});

packages/shim/src/node/constants.js

@@ -0,0 +1,50 @@
+// Linux constant values, to match the platform the process shim reports.
+// O_SYMLINK and other macOS/BSD flags are omitted so feature checks treat platform as linux
+
+export const constantsShim = {
+  // File access checks (fs.access mode).
+  F_OK: 0,
+  X_OK: 1,
+  W_OK: 2,
+  R_OK: 4,
+
+  // open() flags.
+  O_RDONLY: 0,
+  O_WRONLY: 1,
+  O_RDWR: 2,
+  O_CREAT: 64,
+  O_EXCL: 128,
+  O_NOCTTY: 256,
+  O_TRUNC: 512,
+  O_APPEND: 1024,
+  O_DIRECTORY: 65536,
+  O_NOATIME: 262144,
+  O_NOFOLLOW: 131072,
+  O_SYNC: 1052672,
+  O_DSYNC: 4096,
+  O_NONBLOCK: 2048,
+
+  // File type bits (st_mode & S_IFMT).
+  S_IFMT: 61440,
+  S_IFREG: 32768,
+  S_IFDIR: 16384,
+  S_IFCHR: 8192,
+  S_IFBLK: 24576,
+  S_IFIFO: 4096,
+  S_IFLNK: 40960,
+  S_IFSOCK: 49152,
+
+  // Permission bits.
+  S_IRWXU: 448,
+  S_IRUSR: 256,
+  S_IWUSR: 128,
+  S_IXUSR: 64,
+  S_IRWXG: 56,
+  S_IRGRP: 32,
+  S_IWGRP: 16,
+  S_IXGRP: 8,
+  S_IRWXO: 7,
+  S_IROTH: 4,
+  S_IWOTH: 2,
+  S_IXOTH: 1,
+};

packages/shim/src/node/stream.js

@@ -0,0 +1,85 @@
+import { EventEmitter } from "./events.js";
+
+let warned = false;
+
+function warnNoDataFlow(method) {
+  if (warned) {
+    return;
+  }
+
+  warned = true;
+  console.warn(
+    `[shim:stream] ${method}() called, but stream data flow is not implemented. ` +
+      "This plugin needs the full stream shim.",
+  );
+}
+
+export class Stream extends EventEmitter {
+  pipe(destination) {
+    warnNoDataFlow("pipe");
+    return destination;
+  }
+}
+
+export class Readable extends Stream {
+  constructor(options) {
+    super();
+    this.readable = true;
+    this._readableState = { options: options || {} };
+  }
+
+  read() {
+    warnNoDataFlow("read");
+    return null;
+  }
+
+  push() {
+    warnNoDataFlow("push");
+    return false;
+  }
+
+  _read() {}
+}
+
+export class Writable extends Stream {
+  constructor(options) {
+    super();
+    this.writable = true;
+    this._writableState = { options: options || {} };
+  }
+
+  write() {
+    warnNoDataFlow("write");
+    return false;
+  }
+
+  end() {
+    warnNoDataFlow("end");
+    return this;
+  }
+
+  _write() {}
+}
+
+export class Duplex extends Readable {
+  constructor(options) {
+    super(options);
+    this.writable = true;
+  }
+
+  write() {
+    warnNoDataFlow("write");
+    return false;
+  }
+
+  end() {
+    warnNoDataFlow("end");
+    return this;
+  }
+}
+
+export class Transform extends Duplex {
+  _transform() {}
+}
+
+export class PassThrough extends Transform {}

packages/shim/src/node/stream.test.js

@@ -0,0 +1,16 @@
+import { describe, it, expect, vi } from "vitest";
+import { Readable, Writable } from "./stream.js";
+
+describe("stream shim", () => {
+  it("warns once when data-flow methods are used", () => {
+    const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+
+    new Readable().read();
+    new Writable().write("x");
+
+    expect(warn).toHaveBeenCalledTimes(1);
+    expect(warn.mock.calls[0][0]).toContain("[shim:stream]");
+
+    warn.mockRestore();
+  });
+});