1 files changed, 48 insertions, 0 deletions
diff --git a/cli/tests/unit_node/fs_test.ts b/cli/tests/unit_node/fs_test.ts
new file mode 100644
index 000000000..3e9ad4480
--- /dev/null
+++ b/cli/tests/unit_node/fs_test.ts
@@ -0,0 +1,48 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+import {
+  assert,
+  assertThrows,
+} from "../../../test_util/std/testing/asserts.ts";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+import { mkdtempSync, readFileSync, writeFileSync } from "node:fs";
+
+Deno.test(
+  "[node/fs writeFileSync] write file without option",
+  () => {
+    const data = "Hello";
+    const filename = mkdtempSync(join(tmpdir(), "foo-")) + "/test.txt";
+
+    writeFileSync(filename, data);
+    const dataRead = readFileSync(filename, "utf8");
+
+    assert(dataRead === "Hello");
+  },
+);
+
+Deno.test(
+  "[node/fs writeFileSync] write file with option ASCII",
+  () => {
+    const data = "Hello";
+    const filename = mkdtempSync(join(tmpdir(), "foo-")) + "/test.txt";
+
+    writeFileSync(filename, data, { encoding: "ascii" });
+    const dataRead = readFileSync(filename, "utf8");
+
+    assert(dataRead === "Hello");
+  },
+);
+
+Deno.test(
+  "[node/fs writeFileSync] write file throws error when encoding is not implemented",
+  () => {
+    const data = "Hello";
+    const filename = mkdtempSync(join(tmpdir(), "foo-")) + "/test.txt";
+
+    assertThrows(
+      () => writeFileSync(filename, data, { encoding: "utf16le" }),
+      'The value "utf16le" is invalid for option "encoding"',
+    );
+  },
+);