2 files changed, 41 insertions, 11 deletions
diff --git a/std/node/_fs/promises/_fs_readFile_test.ts b/std/node/_fs/promises/_fs_readFile_test.ts
index f5be2318b..1d2097881 100644
--- a/std/node/_fs/promises/_fs_readFile_test.ts
+++ b/std/node/_fs/promises/_fs_readFile_test.ts
@@ -34,6 +34,18 @@ Deno.test("readFileStringObjectSuccess", async function () {
   assertEquals(data, "hello world");
 });
 
+Deno.test("readFileEncodeHexSuccess", async function () {
+  const data: string = await readFile(testData, { encoding: "hex" });
+  assertEquals(typeof data, "string");
+  assertEquals(data as string, "68656c6c6f20776f726c64");
+});
+
+Deno.test("readFileEncodeBase64Success", async function () {
+  const data: string = await readFile(testData, { encoding: "base64" });
+  assertEquals(typeof data, "string");
+  assertEquals(data as string, "aGVsbG8gd29ybGQ=");
+});
+
 Deno.test("readFileStringSuccess", async function () {
   const data: string = await readFile(testData, "utf8");
 
diff --git a/std/node/_fs/promises/_fs_writeFile_test.ts b/std/node/_fs/promises/_fs_writeFile_test.ts
index 777971046..8f6ef0842 100644
--- a/std/node/_fs/promises/_fs_writeFile_test.ts
+++ b/std/node/_fs/promises/_fs_writeFile_test.ts
@@ -6,6 +6,7 @@ import {
   assertThrowsAsync,
 } from "../../../testing/asserts.ts";
 import { writeFile } from "./_fs_writeFile.ts";
+import { TextEncodings } from "../_fs_common.ts";
 
 const decoder = new TextDecoder("utf-8");
 
@@ -35,19 +36,10 @@ Deno.test(
   function testUnsupportedEncoding() {
     assertThrowsAsync(
       async () => {
-        await writeFile("some/path", "some data", "hex");
+        await writeFile("some/path", "some data", "utf16le");
       },
       Error,
-      `Not implemented: "hex" encoding`
-    );
-    assertThrowsAsync(
-      async () => {
-        await writeFile("some/path", "some data", {
-          encoding: "base64",
-        });
-      },
-      Error,
-      `Not implemented: "base64" encoding`
+      `Not implemented: "utf16le" encoding`
     );
   }
 );
@@ -85,6 +77,32 @@ Deno.test(
   }
 );
 
+Deno.test(
+  "Data is written to correct file encodings",
+  async function testCorrectWritePromiseUsingDifferentEncodings() {
+    const encodings = [
+      ["hex", "68656c6c6f20776f726c64"],
+      ["HEX", "68656c6c6f20776f726c64"],
+      ["base64", "aGVsbG8gd29ybGQ="],
+      ["BASE64", "aGVsbG8gd29ybGQ="],
+      ["utf8", "hello world"],
+      ["utf-8", "hello world"],
+    ];
+
+    for (const [encoding, value] of encodings) {
+      await writeFile(
+        "_fs_writeFile_test_file.txt",
+        value,
+        encoding as TextEncodings
+      );
+
+      const data = await Deno.readFile("_fs_writeFile_test_file.txt");
+      await Deno.remove("_fs_writeFile_test_file.txt");
+      assertEquals(decoder.decode(data), "hello world");
+    }
+  }
+);
+
 Deno.test("Mode is correctly set", async function testCorrectFileMode() {
   if (Deno.build.os === "windows") return;
   const filename = "_fs_writeFile_test_file.txt";