Handle media download errors better (#12848)

* Handle media download errors better

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Add test

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Show error if media download failed

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* More tests

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

---------

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

test/customisations/Media-test.ts

@@ -0,0 +1,39 @@
+/*
+Copyright 2024 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import fetchMockJest from "fetch-mock-jest";
+import { mocked } from "jest-mock";
+
+import { mediaFromMxc } from "../../src/customisations/Media";
+import { stubClient } from "../test-utils";
+
+describe("Media", () => {
+    it("should not download error if server returns one", async () => {
+        const cli = stubClient();
+        // eslint-disable-next-line no-restricted-properties
+        mocked(cli.mxcUrlToHttp).mockImplementation(
+            (mxc) => `https://matrix.org/_matrix/media/r0/download/${mxc.slice(6)}`,
+        );
+
+        fetchMockJest.get("https://matrix.org/_matrix/media/r0/download/matrix.org/1234", {
+            status: 404,
+            body: { errcode: "M_NOT_FOUND", error: "Not found" },
+        });
+
+        const media = mediaFromMxc("mxc://matrix.org/1234");
+        await expect(media.downloadSource()).rejects.toThrow("Not found");
+    });
+});