4 files changed, 79 insertions, 3 deletions
diff --git a/test/js/bun/globals.test.js b/test/js/bun/globals.test.js
index 6b004a5f7..fd291d8bc 100644
--- a/test/js/bun/globals.test.js
+++ b/test/js/bun/globals.test.js
@@ -1,4 +1,4 @@
-import { expect, it } from "bun:test";
+import { expect, it, describe } from "bun:test";
 
 it("extendable", () => {
   const classes = [Blob, TextDecoder, TextEncoder, Request, Response, Headers, HTMLRewriter, Bun.Transpiler, Buffer];
@@ -25,6 +25,7 @@ it("writable", () => {
     ["ErrorEvent", ErrorEvent],
     ["CustomEvent", CustomEvent],
     ["CloseEvent", CloseEvent],
+    ["File", File],
   ];
   for (let [name, Class] of classes) {
     globalThis[name] = 123;
@@ -45,8 +46,80 @@ it("name", () => {
     ["HTMLRewriter", HTMLRewriter],
     ["Transpiler", Bun.Transpiler],
     ["Buffer", Buffer],
+    ["File", File],
   ];
   for (let [name, Class] of classes) {
     expect(Class.name).toBe(name);
   }
 });
+
+describe("File", () => {
+  it("constructor", () => {
+    const file = new File(["foo"], "bar.txt", { type: "text/plain;charset=utf-8" });
+    expect(file.name).toBe("bar.txt");
+    expect(file.type).toBe("text/plain;charset=utf-8");
+    expect(file.size).toBe(3);
+    expect(file.lastModified).toBe(0);
+  });
+
+  it("constructor with lastModified", () => {
+    const file = new File(["foo"], "bar.txt", { type: "text/plain;charset=utf-8", lastModified: 123 });
+    expect(file.name).toBe("bar.txt");
+    expect(file.type).toBe("text/plain;charset=utf-8");
+    expect(file.size).toBe(3);
+    expect(file.lastModified).toBe(123);
+  });
+
+  it("constructor with undefined name", () => {
+    const file = new File(["foo"], undefined);
+    expect(file.name).toBe("undefined");
+    expect(file.type).toBe("");
+    expect(file.size).toBe(3);
+    expect(file.lastModified).toBe(0);
+  });
+
+  it("constructor throws invalid args", () => {
+    const invalid = [[], [undefined], [null], [Symbol(), "foo"], [Symbol(), Symbol(), Symbol()]];
+    for (let args of invalid) {
+      expect(() => new File(...args)).toThrow();
+    }
+  });
+
+  it("instanceof", () => {
+    const file = new File(["foo"], "bar.txt", { type: "text/plain;charset=utf-8" });
+    expect(file instanceof File).toBe(true);
+    expect(file instanceof Blob).toBe(true);
+    expect(file instanceof Object).toBe(true);
+    expect(file instanceof Function).toBe(false);
+    const blob = new Blob(["foo"], { type: "text/plain;charset=utf-8" });
+    expect(blob instanceof File).toBe(false);
+  });
+
+  it("extendable", async () => {
+    class Foo extends File {
+      constructor(...args) {
+        super(...args);
+      }
+
+      bar() {
+        return true;
+      }
+
+      text() {
+        return super.text();
+      }
+    }
+    const foo = new Foo(["foo"], "bar.txt", { type: "text/plain;charset=utf-8" });
+    expect(foo instanceof File).toBe(true);
+    expect(foo instanceof Blob).toBe(true);
+    expect(foo instanceof Object).toBe(true);
+    expect(foo instanceof Function).toBe(false);
+    expect(foo instanceof Foo).toBe(true);
+    expect(foo.bar()).toBe(true);
+    expect(foo.name).toBe("bar.txt");
+    expect(foo.type).toBe("text/plain;charset=utf-8");
+    expect(foo.size).toBe(3);
+    expect(foo.lastModified).toBe(0);
+    expect(await foo.text()).toBe("foo");
+  });
+});
diff --git a/test/js/node/buffer.test.js b/test/js/node/buffer.test.js
index 834536020..4040f5ce2 100644
--- a/test/js/node/buffer.test.js
+++ b/test/js/node/buffer.test.js
@@ -1748,7 +1748,7 @@ it("constants", () => {
 });
 
 it("File", () => {
-  expect(BufferModule.File).toBe(Blob);
+  expect(BufferModule.File).toBe(File);
 });
 
 it("transcode", () => {
diff --git a/test/js/web/html/FormData.test.ts b/test/js/web/html/FormData.test.ts
index 8c66abb10..c742bd33e 100644
--- a/test/js/web/html/FormData.test.ts
+++ b/test/js/web/html/FormData.test.ts
@@ -15,9 +15,11 @@ describe("FormData", () => {
 
   it("should be able to append a Blob", async () => {
     const formData = new FormData();
-    formData.append("foo", new Blob(["bar"]));
+    formData.append("foo", new Blob(["bar"]), "mynameis.txt");
     expect(await ((await formData.get("foo")) as Blob)!.text()).toBe("bar");
     expect(formData.getAll("foo")[0] instanceof Blob).toBe(true);
+    expect(formData.getAll("foo")[0] instanceof File).toBe(true);
+    expect((formData.getAll("foo")[0] as File).name).toBe("mynameis.txt");
   });
 
   it("should be able to set a Blob", async () => {
diff --git a/test/js/web/web-globals.test.js b/test/js/web/web-globals.test.js
index 46422c210..9b4c86006 100644
--- a/test/js/web/web-globals.test.js
+++ b/test/js/web/web-globals.test.js
@@ -20,6 +20,7 @@ test("exists", () => {
   expect(typeof Blob !== "undefined").toBe(true);
   expect(typeof FormData !== "undefined").toBe(true);
   expect(typeof Worker !== "undefined").toBe(true);
+  expect(typeof File !== "undefined").toBe(true);
 });
 
 const globalSetters = [