diff --git a/src/platform/web/dom/request/fetch.js b/src/platform/web/dom/request/fetch.js
index 1222c41b..66f1a148 100644
--- a/src/platform/web/dom/request/fetch.js
+++ b/src/platform/web/dom/request/fetch.js
@@ -19,7 +19,7 @@ import {
     AbortError,
     ConnectionError
 } from "../../../../matrix/error.js";
-import {abortOnTimeout} from "./timeout.js";
+import {abortOnTimeout} from "../../../../utils/timeout.js";
 import {addCacheBuster} from "./common.js";
 import {xhrRequest} from "./xhr.js";
 
@@ -121,6 +121,8 @@ export function createFetchRequest(createTimeout, serviceWorkerHandler) {
             return {status, body};
         }, err => {
             if (err.name === "AbortError") {
+                // map DOMException with name AbortError to our own AbortError type
+                // as we don't want DOMExceptions in the protocol layer.
                 throw new AbortError();
             } else if (err instanceof TypeError) {
                 // Network errors are reported as TypeErrors, see
diff --git a/src/platform/web/dom/request/timeout.js b/src/platform/web/dom/request/timeout.js
deleted file mode 100644
index 030e4150..00000000
--- a/src/platform/web/dom/request/timeout.js
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
-Copyright 2020 Bruno Windels <bruno@windels.cloud>
-Copyright 2020 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 {
-    AbortError,
-    ConnectionError
-} from "../../../../matrix/error.js";
-
-
-export function abortOnTimeout(createTimeout, timeoutAmount, requestResult, responsePromise) {
-    const timeout = createTimeout(timeoutAmount);
-    // abort request if timeout finishes first
-    let timedOut = false;
-    timeout.elapsed().then(
-        () => {
-            timedOut = true;
-            requestResult.abort();
-        },
-        () => {}    // ignore AbortError when timeout is aborted
-    );
-    // abort timeout if request finishes first
-    return responsePromise.then(
-        response => {
-            timeout.abort();
-            return response;
-        },
-        err => {
-            timeout.abort();
-            // map error to TimeoutError
-            if (err.name === "AbortError" && timedOut) {
-                throw new ConnectionError(`Request timed out after ${timeoutAmount}ms`, true);
-            } else {
-                throw err;
-            }
-        }
-    );
-}
diff --git a/src/utils/timeout.js b/src/utils/timeout.js
new file mode 100644
index 00000000..886d6a50
--- /dev/null
+++ b/src/utils/timeout.js
@@ -0,0 +1,100 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+Copyright 2020 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 {ConnectionError} from "../matrix/error.js";
+
+
+export function abortOnTimeout(createTimeout, timeoutAmount, requestResult, responsePromise) {
+    const timeout = createTimeout(timeoutAmount);
+    // abort request if timeout finishes first
+    let timedOut = false;
+    timeout.elapsed().then(
+        () => {
+            timedOut = true;
+            requestResult.abort();
+        },
+        () => {}    // ignore AbortError when timeout is aborted
+    );
+    // abort timeout if request finishes first
+    return responsePromise.then(
+        response => {
+            timeout.abort();
+            return response;
+        },
+        err => {
+            timeout.abort();
+            // map error to TimeoutError
+            if (err.name === "AbortError" && timedOut) {
+                throw new ConnectionError(`Request timed out after ${timeoutAmount}ms`, true);
+            } else {
+                throw err;
+            }
+        }
+    );
+}
+
+// because impunity only takes one entrypoint currently,
+// these tests aren't run by yarn test as that does not
+// include platform specific code,
+// and this file is only included by platform specific code,
+// see how to run in package.json and replace src/main.js with this file.
+import {Clock} from "../mocks/Clock.js";
+import {AbortError} from "../matrix/error.js";
+export function tests() {
+    function createRequest() {
+        let request = {
+            abort() {
+                this.aborted = true;
+                this.reject(new AbortError());
+            }
+        };
+        request.responsePromise = new Promise((resolve, reject) => {
+            request.resolve = resolve;
+            request.reject = reject;
+        });
+        return request;
+    }
+
+    return {
+        "ConnectionError on timeout": async assert => {
+            const clock = new Clock();
+            const request = createRequest();
+            const promise = abortOnTimeout(clock.createTimeout, 10000, request, request.responsePromise);
+            clock.elapse(10000);
+            await assert.rejects(promise, ConnectionError);
+            assert(request.aborted);
+        },
+        "Abort is canceled once response resolves": async assert => {
+            const clock = new Clock();
+            const request = createRequest();
+            const promise = abortOnTimeout(clock.createTimeout, 10000, request, request.responsePromise);
+            request.resolve(5);
+            clock.elapse(10000);
+            assert(!request.aborted);
+            assert.equal(await promise, 5);
+        },
+        "AbortError from request is not mapped to ConnectionError": async assert => {
+            const clock = new Clock();
+            const request = createRequest();
+            const promise = abortOnTimeout(clock.createTimeout, 10000, request, request.responsePromise);
+            request.reject(new AbortError());
+            assert(!request.aborted);
+            assert.rejects(promise, AbortError);
+        }
+    }
+
+}