denoland-deno/cli/tests/unit/write_text_file_test.ts

import { unitTest, assert, assertEquals } from "./test_util.ts";

unitTest(
  { perms: { read: true, write: true } },
  function writeTextFileSyncSuccess(): void {
    const filename = Deno.makeTempDirSync() + "/test.txt";
    Deno.writeTextFileSync(filename, "Hello");
    const dataRead = Deno.readTextFileSync(filename);
    assertEquals("Hello", dataRead);
  }
);

unitTest({ perms: { write: true } }, function writeTextFileSyncFail(): void {
  const filename = "/baddir/test.txt";
  // The following should fail because /baddir doesn't exist (hopefully).
  let caughtError = false;
  try {
    Deno.writeTextFileSync(filename, "hello");
  } catch (e) {
    caughtError = true;
    assert(e instanceof Deno.errors.NotFound);
  }
  assert(caughtError);
});

unitTest({ perms: { write: false } }, function writeTextFileSyncPerm(): void {
  const filename = "/baddir/test.txt";
  // The following should fail due to no write permission
  let caughtError = false;
  try {
    Deno.writeTextFileSync(filename, "Hello");
  } catch (e) {
    caughtError = true;
    assert(e instanceof Deno.errors.PermissionDenied);
  }
  assert(caughtError);
});

unitTest(
  { perms: { read: true, write: true } },
  async function writeTextFileSuccess(): Promise<void> {
    const filename = Deno.makeTempDirSync() + "/test.txt";
    await Deno.writeTextFile(filename, "Hello");
    const dataRead = Deno.readTextFileSync(filename);
    assertEquals("Hello", dataRead);
  }
);

unitTest(
  { perms: { read: true, write: true } },
  async function writeTextFileNotFound(): Promise<void> {
    const filename = "/baddir/test.txt";
    // The following should fail because /baddir doesn't exist (hopefully).
    let caughtError = false;
    try {
      await Deno.writeTextFile(filename, "Hello");
    } catch (e) {
      caughtError = true;
      assert(e instanceof Deno.errors.NotFound);
    }
    assert(caughtError);
  }
);

unitTest(
  { perms: { write: false } },
  async function writeTextFilePerm(): Promise<void> {
    const filename = "/baddir/test.txt";
    // The following should fail due to no write permission
    let caughtError = false;
    try {
      await Deno.writeTextFile(filename, "Hello");
    } catch (e) {
      caughtError = true;
      assert(e instanceof Deno.errors.PermissionDenied);
    }
    assert(caughtError);
  }
);