diff --git a/package.json b/package.json
index 37a15e2..1235985 100644
--- a/package.json
+++ b/package.json
@@ -16,10 +16,11 @@
     "examples": "serve .",
     "predeploy": "npm run test",
     "prepublishOnly": "npm run predeploy",
-    "test": "node test"
+    "test": "node test/index.js"
   },
   "devDependencies": {
     "browser-env": "^3.3.0",
+    "resize-observer-polyfill": "^1.5.1",
     "serve": "^14.0.0",
     "tape": "^5.2.2"
   },
diff --git a/snabbdom-containerquery.js b/snabbdom-containerquery.js
index 5ee30c4..dab071f 100644
--- a/snabbdom-containerquery.js
+++ b/snabbdom-containerquery.js
@@ -3,7 +3,7 @@
 
 // today it's more performant to have 1 resizeObserver observe multiple elements rather than 1 per element.
 // see https://groups.google.com/a/chromium.org/g/blink-dev/c/z6ienONUb5A/m/F5-VcUZtBAAJ
-const observer = new ResizeObserver(function (entries) {
+const observer = new window.ResizeObserver(function (entries) {
 	for (const entry of entries) {
 		const breakpoints = JSON.parse(entry.target.dataset.breakpoints);
 
diff --git a/test/index.js b/test/index.js
new file mode 100644
index 0000000..15d96da
--- /dev/null
+++ b/test/index.js
@@ -0,0 +1,15 @@
+import browserEnv     from 'browser-env'
+import ResizeObserver from 'resize-observer-polyfill'
+
+
+browserEnv()
+
+// browser-env doesn't provide browser APIs beyond pure DOM/window stuff
+window.ResizeObserver = ResizeObserver
+window.requestAnimationFrame = function () { }
+
+async function main () {
+	await import('./test.js');
+}
+
+main();
diff --git a/test.js b/test/test.js
similarity index 96%
rename from test.js
rename to test/test.js
index 47b54c6..1232205 100644
--- a/test.js
+++ b/test/test.js
@@ -1,12 +1,8 @@
-import browserEnv from 'browser-env'
-import snabby     from './index.js'
+import snabby     from '../index.js'
 import { h }      from 'snabbdom' // helper function for creating vnodes
 import test       from 'tape'
 
 
-browserEnv()
-
-
 test('creation', function (t) {
   t.plan(2)