Modernize http-api - move from browser-request to fetch (#2719)

spec/unit/http-api/__snapshots__/index.spec.ts.snap

@@ -0,0 +1,11 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`MatrixHttpApi should return expected object from \`getContentUri\` 1`] = `
+{
+  "base": "http://baseUrl",
+  "params": {
+    "access_token": "token",
+  },
+  "path": "/_matrix/media/r0/upload",
+}
+`;

spec/unit/http-api/fetch.spec.ts

@@ -0,0 +1,223 @@
+/*
+Copyright 2022 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 { FetchHttpApi } from "../../../src/http-api/fetch";
+import { TypedEventEmitter } from "../../../src/models/typed-event-emitter";
+import { ClientPrefix, HttpApiEvent, HttpApiEventHandlerMap, IdentityPrefix, IHttpOpts, Method } from "../../../src";
+import { emitPromise } from "../../test-utils/test-utils";
+
+describe("FetchHttpApi", () => {
+    const baseUrl = "http://baseUrl";
+    const idBaseUrl = "http://idBaseUrl";
+    const prefix = ClientPrefix.V3;
+
+    it("should support aborting multiple times", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix, fetchFn });
+
+        api.request(Method.Get, "/foo");
+        api.request(Method.Get, "/baz");
+        expect(fetchFn.mock.calls[0][0].href.endsWith("/foo")).toBeTruthy();
+        expect(fetchFn.mock.calls[0][1].signal.aborted).toBeFalsy();
+        expect(fetchFn.mock.calls[1][0].href.endsWith("/baz")).toBeTruthy();
+        expect(fetchFn.mock.calls[1][1].signal.aborted).toBeFalsy();
+
+        api.abort();
+        expect(fetchFn.mock.calls[0][1].signal.aborted).toBeTruthy();
+        expect(fetchFn.mock.calls[1][1].signal.aborted).toBeTruthy();
+
+        api.request(Method.Get, "/bar");
+        expect(fetchFn.mock.calls[2][0].href.endsWith("/bar")).toBeTruthy();
+        expect(fetchFn.mock.calls[2][1].signal.aborted).toBeFalsy();
+
+        api.abort();
+        expect(fetchFn.mock.calls[2][1].signal.aborted).toBeTruthy();
+    });
+
+    it("should fall back to global fetch if fetchFn not provided", () => {
+        global.fetch = jest.fn();
+        expect(global.fetch).not.toHaveBeenCalled();
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        api.fetch("test");
+        expect(global.fetch).toHaveBeenCalled();
+    });
+
+    it("should update identity server base url", () => {
+        const api = new FetchHttpApi<IHttpOpts>(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        expect(api.opts.idBaseUrl).toBeUndefined();
+        api.setIdBaseUrl("https://id.foo.bar");
+        expect(api.opts.idBaseUrl).toBe("https://id.foo.bar");
+    });
+
+    describe("idServerRequest", () => {
+        it("should throw if no idBaseUrl", () => {
+            const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+            expect(() => api.idServerRequest(Method.Get, "/test", {}, IdentityPrefix.V2))
+                .toThrow("No identity server base URL set");
+        });
+
+        it("should send params as query string for GET requests", () => {
+            const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+            const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, idBaseUrl, prefix, fetchFn });
+            api.idServerRequest(Method.Get, "/test", { foo: "bar", via: ["a", "b"] }, IdentityPrefix.V2);
+            expect(fetchFn.mock.calls[0][0].searchParams.get("foo")).toBe("bar");
+            expect(fetchFn.mock.calls[0][0].searchParams.getAll("via")).toEqual(["a", "b"]);
+        });
+
+        it("should send params as body for non-GET requests", () => {
+            const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+            const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, idBaseUrl, prefix, fetchFn });
+            const params = { foo: "bar", via: ["a", "b"] };
+            api.idServerRequest(Method.Post, "/test", params, IdentityPrefix.V2);
+            expect(fetchFn.mock.calls[0][0].searchParams.get("foo")).not.toBe("bar");
+            expect(JSON.parse(fetchFn.mock.calls[0][1].body)).toStrictEqual(params);
+        });
+
+        it("should add Authorization header if token provided", () => {
+            const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+            const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, idBaseUrl, prefix, fetchFn });
+            api.idServerRequest(Method.Post, "/test", {}, IdentityPrefix.V2, "token");
+            expect(fetchFn.mock.calls[0][1].headers.Authorization).toBe("Bearer token");
+        });
+    });
+
+    it("should return the Response object if onlyData=false", async () => {
+        const res = { ok: true };
+        const fetchFn = jest.fn().mockResolvedValue(res);
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix, fetchFn, onlyData: false });
+        await expect(api.requestOtherUrl(Method.Get, "http://url")).resolves.toBe(res);
+    });
+
+    it("should return text if json=false", async () => {
+        const text = "418 I'm a teapot";
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true, text: jest.fn().mockResolvedValue(text) });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix, fetchFn, onlyData: true });
+        await expect(api.requestOtherUrl(Method.Get, "http://url", undefined, {
+            json: false,
+        })).resolves.toBe(text);
+    });
+
+    it("should send token via query params if useAuthorizationHeader=false", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            fetchFn,
+            accessToken: "token",
+            useAuthorizationHeader: false,
+        });
+        api.authedRequest(Method.Get, "/path");
+        expect(fetchFn.mock.calls[0][0].searchParams.get("access_token")).toBe("token");
+    });
+
+    it("should send token via headers by default", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            fetchFn,
+            accessToken: "token",
+        });
+        api.authedRequest(Method.Get, "/path");
+        expect(fetchFn.mock.calls[0][1].headers["Authorization"]).toBe("Bearer token");
+    });
+
+    it("should not send a token if not calling `authedRequest`", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            fetchFn,
+            accessToken: "token",
+        });
+        api.request(Method.Get, "/path");
+        expect(fetchFn.mock.calls[0][0].searchParams.get("access_token")).toBeFalsy();
+        expect(fetchFn.mock.calls[0][1].headers["Authorization"]).toBeFalsy();
+    });
+
+    it("should ensure no token is leaked out via query params if sending via headers", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            fetchFn,
+            accessToken: "token",
+            useAuthorizationHeader: true,
+        });
+        api.authedRequest(Method.Get, "/path", { access_token: "123" });
+        expect(fetchFn.mock.calls[0][0].searchParams.get("access_token")).toBeFalsy();
+        expect(fetchFn.mock.calls[0][1].headers["Authorization"]).toBe("Bearer token");
+    });
+
+    it("should not override manually specified access token via query params", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            fetchFn,
+            accessToken: "token",
+            useAuthorizationHeader: false,
+        });
+        api.authedRequest(Method.Get, "/path", { access_token: "RealToken" });
+        expect(fetchFn.mock.calls[0][0].searchParams.get("access_token")).toBe("RealToken");
+    });
+
+    it("should not override manually specified access token via header", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            fetchFn,
+            accessToken: "token",
+            useAuthorizationHeader: true,
+        });
+        api.authedRequest(Method.Get, "/path", undefined, undefined, {
+            headers: { Authorization: "Bearer RealToken" },
+        });
+        expect(fetchFn.mock.calls[0][1].headers["Authorization"]).toBe("Bearer RealToken");
+    });
+
+    it("should not override Accept header", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new FetchHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix, fetchFn });
+        api.authedRequest(Method.Get, "/path", undefined, undefined, {
+            headers: { Accept: "text/html" },
+        });
+        expect(fetchFn.mock.calls[0][1].headers["Accept"]).toBe("text/html");
+    });
+
+    it("should emit NoConsent when given errcode=M_CONTENT_NOT_GIVEN", async () => {
+        const fetchFn = jest.fn().mockResolvedValue({
+            ok: false,
+            headers: {
+                get(name: string): string | null {
+                    return name === "Content-Type" ? "application/json" : null;
+                },
+            },
+            text: jest.fn().mockResolvedValue(JSON.stringify({
+                errcode: "M_CONSENT_NOT_GIVEN",
+                error: "Ye shall ask for consent",
+            })),
+        });
+        const emitter = new TypedEventEmitter<HttpApiEvent, HttpApiEventHandlerMap>();
+        const api = new FetchHttpApi(emitter, { baseUrl, prefix, fetchFn });
+
+        await Promise.all([
+            emitPromise(emitter, HttpApiEvent.NoConsent),
+            expect(api.authedRequest(Method.Get, "/path")).rejects.toThrow("Ye shall ask for consent"),
+        ]);
+    });
+});

spec/unit/http-api/index.spec.ts

@@ -0,0 +1,228 @@
+/*
+Copyright 2022 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 DOMException from "domexception";
+import { mocked } from "jest-mock";
+
+import { ClientPrefix, MatrixHttpApi, Method, UploadResponse } from "../../../src";
+import { TypedEventEmitter } from "../../../src/models/typed-event-emitter";
+
+type Writeable<T> = { -readonly [P in keyof T]: T[P] };
+
+jest.useFakeTimers();
+
+describe("MatrixHttpApi", () => {
+    const baseUrl = "http://baseUrl";
+    const prefix = ClientPrefix.V3;
+
+    let xhr: Partial<Writeable<XMLHttpRequest>>;
+    let upload: Promise<UploadResponse>;
+
+    const DONE = 0;
+
+    global.DOMException = DOMException;
+
+    beforeEach(() => {
+        xhr = {
+            upload: {} as XMLHttpRequestUpload,
+            open: jest.fn(),
+            send: jest.fn(),
+            abort: jest.fn(),
+            setRequestHeader: jest.fn(),
+            onreadystatechange: undefined,
+            getResponseHeader: jest.fn(),
+        };
+        // We stub out XHR here as it is not available in JSDOM
+        // @ts-ignore
+        global.XMLHttpRequest = jest.fn().mockReturnValue(xhr);
+        // @ts-ignore
+        global.XMLHttpRequest.DONE = DONE;
+    });
+
+    afterEach(() => {
+        upload?.catch(() => {});
+        // Abort any remaining requests
+        xhr.readyState = DONE;
+        xhr.status = 0;
+        // @ts-ignore
+        xhr.onreadystatechange?.(new Event("test"));
+    });
+
+    it("should fall back to `fetch` where xhr is unavailable", () => {
+        global.XMLHttpRequest = undefined;
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true, json: jest.fn().mockResolvedValue({}) });
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix, fetchFn });
+        upload = api.uploadContent({} as File);
+        expect(fetchFn).toHaveBeenCalled();
+    });
+
+    it("should prefer xhr where available", () => {
+        const fetchFn = jest.fn().mockResolvedValue({ ok: true });
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix, fetchFn });
+        upload = api.uploadContent({} as File);
+        expect(fetchFn).not.toHaveBeenCalled();
+        expect(xhr.open).toHaveBeenCalled();
+    });
+
+    it("should send access token in query params if header disabled", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            accessToken: "token",
+            useAuthorizationHeader: false,
+        });
+        upload = api.uploadContent({} as File);
+        expect(xhr.open)
+            .toHaveBeenCalledWith(Method.Post, baseUrl.toLowerCase() + "/_matrix/media/r0/upload?access_token=token");
+        expect(xhr.setRequestHeader).not.toHaveBeenCalledWith("Authorization");
+    });
+
+    it("should send access token in header by default", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), {
+            baseUrl,
+            prefix,
+            accessToken: "token",
+        });
+        upload = api.uploadContent({} as File);
+        expect(xhr.open).toHaveBeenCalledWith(Method.Post, baseUrl.toLowerCase() + "/_matrix/media/r0/upload");
+        expect(xhr.setRequestHeader).toHaveBeenCalledWith("Authorization", "Bearer token");
+    });
+
+    it("should include filename by default", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File, { name: "name" });
+        expect(xhr.open)
+            .toHaveBeenCalledWith(Method.Post, baseUrl.toLowerCase() + "/_matrix/media/r0/upload?filename=name");
+    });
+
+    it("should allow not sending the filename", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File, { name: "name", includeFilename: false });
+        expect(xhr.open).toHaveBeenCalledWith(Method.Post, baseUrl.toLowerCase() + "/_matrix/media/r0/upload");
+    });
+
+    it("should abort xhr when the upload is aborted", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+        api.cancelUpload(upload);
+        expect(xhr.abort).toHaveBeenCalled();
+        return expect(upload).rejects.toThrow("Aborted");
+    });
+
+    it("should timeout if no progress in 30s", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+        jest.advanceTimersByTime(25000);
+        // @ts-ignore
+        xhr.upload.onprogress(new Event("progress", { loaded: 1, total: 100 }));
+        jest.advanceTimersByTime(25000);
+        expect(xhr.abort).not.toHaveBeenCalled();
+        jest.advanceTimersByTime(5000);
+        expect(xhr.abort).toHaveBeenCalled();
+    });
+
+    it("should call progressHandler", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        const progressHandler = jest.fn();
+        upload = api.uploadContent({} as File, { progressHandler });
+        const progressEvent = new Event("progress") as ProgressEvent;
+        Object.assign(progressEvent, { loaded: 1, total: 100 });
+        // @ts-ignore
+        xhr.upload.onprogress(progressEvent);
+        expect(progressHandler).toHaveBeenCalledWith({ loaded: 1, total: 100 });
+
+        Object.assign(progressEvent, { loaded: 95, total: 100 });
+        // @ts-ignore
+        xhr.upload.onprogress(progressEvent);
+        expect(progressHandler).toHaveBeenCalledWith({ loaded: 95, total: 100 });
+    });
+
+    it("should error when no response body", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+
+        xhr.readyState = DONE;
+        xhr.responseText = "";
+        xhr.status = 200;
+        // @ts-ignore
+        xhr.onreadystatechange?.(new Event("test"));
+
+        return expect(upload).rejects.toThrow("No response body.");
+    });
+
+    it("should error on a 400-code", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+
+        xhr.readyState = DONE;
+        xhr.responseText = '{"errcode": "M_NOT_FOUND", "error": "Not found"}';
+        xhr.status = 404;
+        mocked(xhr.getResponseHeader).mockReturnValue("application/json");
+        // @ts-ignore
+        xhr.onreadystatechange?.(new Event("test"));
+
+        return expect(upload).rejects.toThrow("Not found");
+    });
+
+    it("should return response on successful upload", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+
+        xhr.readyState = DONE;
+        xhr.responseText = '{"content_uri": "mxc://server/foobar"}';
+        xhr.status = 200;
+        mocked(xhr.getResponseHeader).mockReturnValue("application/json");
+        // @ts-ignore
+        xhr.onreadystatechange?.(new Event("test"));
+
+        return expect(upload).resolves.toStrictEqual({ content_uri: "mxc://server/foobar" });
+    });
+
+    it("should abort xhr when calling `cancelUpload`", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+        expect(api.cancelUpload(upload)).toBeTruthy();
+        expect(xhr.abort).toHaveBeenCalled();
+    });
+
+    it("should return false when `cancelUpload` is called but unsuccessful", async () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+
+        xhr.readyState = DONE;
+        xhr.status = 500;
+        mocked(xhr.getResponseHeader).mockReturnValue("application/json");
+        // @ts-ignore
+        xhr.onreadystatechange?.(new Event("test"));
+        await upload.catch(() => {});
+
+        expect(api.cancelUpload(upload)).toBeFalsy();
+        expect(xhr.abort).not.toHaveBeenCalled();
+    });
+
+    it("should return active uploads in `getCurrentUploads`", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix });
+        upload = api.uploadContent({} as File);
+        expect(api.getCurrentUploads().find(u => u.promise === upload)).toBeTruthy();
+        api.cancelUpload(upload);
+        expect(api.getCurrentUploads().find(u => u.promise === upload)).toBeFalsy();
+    });
+
+    it("should return expected object from `getContentUri`", () => {
+        const api = new MatrixHttpApi(new TypedEventEmitter<any, any>(), { baseUrl, prefix, accessToken: "token" });
+        expect(api.getContentUri()).toMatchSnapshot();
+    });
+});

spec/unit/http-api/utils.spec.ts

@@ -0,0 +1,183 @@
+/*
+Copyright 2022 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 { mocked } from "jest-mock";
+
+import {
+    anySignal,
+    ConnectionError,
+    MatrixError,
+    parseErrorResponse,
+    retryNetworkOperation,
+    timeoutSignal,
+} from "../../../src";
+import { sleep } from "../../../src/utils";
+
+jest.mock("../../../src/utils");
+
+describe("timeoutSignal", () => {
+    jest.useFakeTimers();
+
+    it("should fire abort signal after specified timeout", () => {
+        const signal = timeoutSignal(3000);
+        const onabort = jest.fn();
+        signal.onabort = onabort;
+        expect(signal.aborted).toBeFalsy();
+        expect(onabort).not.toHaveBeenCalled();
+
+        jest.advanceTimersByTime(3000);
+        expect(signal.aborted).toBeTruthy();
+        expect(onabort).toHaveBeenCalled();
+    });
+});
+
+describe("anySignal", () => {
+    jest.useFakeTimers();
+
+    it("should fire when any signal fires", () => {
+        const { signal } = anySignal([
+            timeoutSignal(3000),
+            timeoutSignal(2000),
+        ]);
+
+        const onabort = jest.fn();
+        signal.onabort = onabort;
+        expect(signal.aborted).toBeFalsy();
+        expect(onabort).not.toHaveBeenCalled();
+
+        jest.advanceTimersByTime(2000);
+        expect(signal.aborted).toBeTruthy();
+        expect(onabort).toHaveBeenCalled();
+    });
+
+    it("should cleanup when instructed", () => {
+        const { signal, cleanup } = anySignal([
+            timeoutSignal(3000),
+            timeoutSignal(2000),
+        ]);
+
+        const onabort = jest.fn();
+        signal.onabort = onabort;
+        expect(signal.aborted).toBeFalsy();
+        expect(onabort).not.toHaveBeenCalled();
+
+        cleanup();
+        jest.advanceTimersByTime(2000);
+        expect(signal.aborted).toBeFalsy();
+        expect(onabort).not.toHaveBeenCalled();
+    });
+
+    it("should abort immediately if passed an aborted signal", () => {
+        const controller = new AbortController();
+        controller.abort();
+        const { signal } = anySignal([controller.signal]);
+        expect(signal.aborted).toBeTruthy();
+    });
+});
+
+describe("parseErrorResponse", () => {
+    it("should resolve Matrix Errors from XHR", () => {
+        expect(parseErrorResponse({
+            getResponseHeader(name: string): string | null {
+                return name === "Content-Type" ? "application/json" : null;
+            },
+            status: 500,
+        } as XMLHttpRequest, '{"errcode": "TEST"}')).toStrictEqual(new MatrixError({
+            errcode: "TEST",
+        }, 500));
+    });
+
+    it("should resolve Matrix Errors from fetch", () => {
+        expect(parseErrorResponse({
+            headers: {
+                get(name: string): string | null {
+                    return name === "Content-Type" ? "application/json" : null;
+                },
+            },
+            status: 500,
+        } as Response, '{"errcode": "TEST"}')).toStrictEqual(new MatrixError({
+            errcode: "TEST",
+        }, 500));
+    });
+
+    it("should handle no type gracefully", () => {
+        expect(parseErrorResponse({
+            headers: {
+                get(name: string): string | null {
+                    return null;
+                },
+            },
+            status: 500,
+        } as Response, '{"errcode": "TEST"}')).toStrictEqual(new Error("Server returned 500 error"));
+    });
+
+    it("should handle invalid type gracefully", () => {
+        expect(parseErrorResponse({
+            headers: {
+                get(name: string): string | null {
+                    return name === "Content-Type" ? " " : null;
+                },
+            },
+            status: 500,
+        } as Response, '{"errcode": "TEST"}'))
+            .toStrictEqual(new Error("Error parsing Content-Type ' ': TypeError: invalid media type"));
+    });
+
+    it("should handle plaintext errors", () => {
+        expect(parseErrorResponse({
+            headers: {
+                get(name: string): string | null {
+                    return name === "Content-Type" ? "text/plain" : null;
+                },
+            },
+            status: 418,
+        } as Response, "I'm a teapot")).toStrictEqual(new Error("Server returned 418 error: I'm a teapot"));
+    });
+});
+
+describe("retryNetworkOperation", () => {
+    it("should retry given number of times with exponential sleeps", async () => {
+        const err = new ConnectionError("test");
+        const fn = jest.fn().mockRejectedValue(err);
+        mocked(sleep).mockResolvedValue(undefined);
+        await expect(retryNetworkOperation(4, fn)).rejects.toThrow(err);
+        expect(fn).toHaveBeenCalledTimes(4);
+        expect(mocked(sleep)).toHaveBeenCalledTimes(3);
+        expect(mocked(sleep).mock.calls[0][0]).toBe(2000);
+        expect(mocked(sleep).mock.calls[1][0]).toBe(4000);
+        expect(mocked(sleep).mock.calls[2][0]).toBe(8000);
+    });
+
+    it("should bail out on errors other than ConnectionError", async () => {
+        const err = new TypeError("invalid JSON");
+        const fn = jest.fn().mockRejectedValue(err);
+        mocked(sleep).mockResolvedValue(undefined);
+        await expect(retryNetworkOperation(3, fn)).rejects.toThrow(err);
+        expect(fn).toHaveBeenCalledTimes(1);
+    });
+
+    it("should return newest ConnectionError when giving up", async () => {
+        const err1 = new ConnectionError("test1");
+        const err2 = new ConnectionError("test2");
+        const err3 = new ConnectionError("test3");
+        const errors = [err1, err2, err3];
+        const fn = jest.fn().mockImplementation(() => {
+            throw errors.shift();
+        });
+        mocked(sleep).mockResolvedValue(undefined);
+        await expect(retryNetworkOperation(3, fn)).rejects.toThrow(err3);
+    });
+});