1 files changed, 242 insertions, 0 deletions
diff --git a/tests/unit/filereader_test.ts b/tests/unit/filereader_test.ts
new file mode 100644
index 000000000..158cf5383
--- /dev/null
+++ b/tests/unit/filereader_test.ts
@@ -0,0 +1,242 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+import { assertEquals } from "./test_util.ts";
+
+Deno.test(function fileReaderConstruct() {
+  const fr = new FileReader();
+  assertEquals(fr.readyState, FileReader.EMPTY);
+
+  assertEquals(FileReader.EMPTY, 0);
+  assertEquals(FileReader.LOADING, 1);
+  assertEquals(FileReader.DONE, 2);
+});
+
+Deno.test(async function fileReaderLoadBlob() {
+  await new Promise<void>((resolve) => {
+    const fr = new FileReader();
+    const b1 = new Blob(["Hello World"]);
+
+    assertEquals(fr.readyState, FileReader.EMPTY);
+
+    const hasOnEvents = {
+      load: false,
+      loadend: false,
+      loadstart: false,
+      progress: 0,
+    };
+    const hasDispatchedEvents = {
+      load: false,
+      loadend: false,
+      loadstart: false,
+      progress: 0,
+    };
+    let result: string | null = null;
+
+    fr.addEventListener("load", () => {
+      hasDispatchedEvents.load = true;
+    });
+    fr.addEventListener("loadend", () => {
+      hasDispatchedEvents.loadend = true;
+    });
+    fr.addEventListener("loadstart", () => {
+      hasDispatchedEvents.loadstart = true;
+    });
+    fr.addEventListener("progress", () => {
+      hasDispatchedEvents.progress += 1;
+    });
+
+    fr.onloadstart = () => {
+      hasOnEvents.loadstart = true;
+    };
+    fr.onprogress = () => {
+      assertEquals(fr.readyState, FileReader.LOADING);
+
+      hasOnEvents.progress += 1;
+    };
+    fr.onload = () => {
+      hasOnEvents.load = true;
+    };
+    fr.onloadend = (ev) => {
+      hasOnEvents.loadend = true;
+      result = fr.result as string;
+
+      assertEquals(hasOnEvents.loadstart, true);
+      assertEquals(hasDispatchedEvents.loadstart, true);
+      assertEquals(hasOnEvents.load, true);
+      assertEquals(hasDispatchedEvents.load, true);
+      assertEquals(hasOnEvents.loadend, true);
+      assertEquals(hasDispatchedEvents.loadend, true);
+
+      assertEquals(fr.readyState, FileReader.DONE);
+
+      assertEquals(result, "Hello World");
+      assertEquals(ev.lengthComputable, true);
+      resolve();
+    };
+
+    fr.readAsText(b1);
+  });
+});
+
+Deno.test(async function fileReaderLoadBlobDouble() {
+  // impl note from https://w3c.github.io/FileAPI/
+  // Event handler for the load or error events could have started another load,
+  // if that happens the loadend event for the first load is not fired
+
+  const fr = new FileReader();
+  const b1 = new Blob(["First load"]);
+  const b2 = new Blob(["Second load"]);
+
+  await new Promise<void>((resolve) => {
+    let result: string | null = null;
+
+    fr.onload = () => {
+      result = fr.result as string;
+      assertEquals(result === "First load" || result === "Second load", true);
+
+      if (result === "First load") {
+        fr.readAsText(b2);
+      }
+    };
+    fr.onloadend = () => {
+      assertEquals(result, "Second load");
+
+      resolve();
+    };
+
+    fr.readAsText(b1);
+  });
+});
+
+Deno.test(async function fileReaderLoadBlobArrayBuffer() {
+  await new Promise<void>((resolve) => {
+    const fr = new FileReader();
+    const b1 = new Blob(["Hello World"]);
+    let result: ArrayBuffer | null = null;
+
+    fr.onloadend = (ev) => {
+      assertEquals(fr.result instanceof ArrayBuffer, true);
+      result = fr.result as ArrayBuffer;
+
+      const decoder = new TextDecoder();
+      const text = decoder.decode(result);
+
+      assertEquals(text, "Hello World");
+      assertEquals(ev.lengthComputable, true);
+      resolve();
+    };
+
+    fr.readAsArrayBuffer(b1);
+  });
+});
+
+Deno.test(async function fileReaderLoadBlobDataUrl() {
+  await new Promise<void>((resolve) => {
+    const fr = new FileReader();
+    const b1 = new Blob(["Hello World"]);
+    let result: string | null = null;
+
+    fr.onloadend = (ev) => {
+      result = fr.result as string;
+      assertEquals(
+        result,
+        "data:application/octet-stream;base64,SGVsbG8gV29ybGQ=",
+      );
+      assertEquals(ev.lengthComputable, true);
+      resolve();
+    };
+
+    fr.readAsDataURL(b1);
+  });
+});
+
+Deno.test(async function fileReaderLoadBlobAbort() {
+  await new Promise<void>((resolve) => {
+    const fr = new FileReader();
+    const b1 = new Blob(["Hello World"]);
+
+    const hasOnEvents = {
+      load: false,
+      loadend: false,
+      abort: false,
+    };
+
+    fr.onload = () => {
+      hasOnEvents.load = true;
+    };
+    fr.onloadend = (ev) => {
+      hasOnEvents.loadend = true;
+
+      assertEquals(hasOnEvents.load, false);
+      assertEquals(hasOnEvents.loadend, true);
+      assertEquals(hasOnEvents.abort, true);
+
+      assertEquals(fr.readyState, FileReader.DONE);
+      assertEquals(fr.result, null);
+      assertEquals(ev.lengthComputable, false);
+      resolve();
+    };
+    fr.onabort = () => {
+      hasOnEvents.abort = true;
+    };
+
+    fr.readAsDataURL(b1);
+    fr.abort();
+  });
+});
+
+Deno.test(async function fileReaderLoadBlobAbort() {
+  await new Promise<void>((resolve) => {
+    const fr = new FileReader();
+    const b1 = new Blob(["Hello World"]);
+
+    const hasOnEvents = {
+      load: false,
+      loadend: false,
+      abort: false,
+    };
+
+    fr.onload = () => {
+      hasOnEvents.load = true;
+    };
+    fr.onloadend = (ev) => {
+      hasOnEvents.loadend = true;
+
+      assertEquals(hasOnEvents.load, false);
+      assertEquals(hasOnEvents.loadend, true);
+      assertEquals(hasOnEvents.abort, true);
+
+      assertEquals(fr.readyState, FileReader.DONE);
+      assertEquals(fr.result, null);
+      assertEquals(ev.lengthComputable, false);
+      resolve();
+    };
+    fr.onabort = () => {
+      hasOnEvents.abort = true;
+    };
+
+    fr.readAsDataURL(b1);
+    fr.abort();
+  });
+});
+
+Deno.test(
+  async function fileReaderDispatchesEventsInCorrectOrder() {
+    await new Promise<void>((resolve) => {
+      const fr = new FileReader();
+      const b1 = new Blob(["Hello World"]);
+      let out = "";
+      fr.addEventListener("loadend", () => {
+        out += "1";
+      });
+      fr.onloadend = (_ev) => {
+        out += "2";
+      };
+      fr.addEventListener("loadend", () => {
+        assertEquals(out, "12");
+        resolve();
+      });
+
+      fr.readAsDataURL(b1);
+    });
+  },
+);