Switch from QUnit to Jasmine.

js/tests/helpers/fixture.js

@@ -0,0 +1,20 @@
+const fixtureId = 'fixture'
+
+export const getFixture = () => {
+  let fixtureEl = document.getElementById(fixtureId)
+
+  if (!fixtureEl) {
+    fixtureEl = document.createElement('div')
+    fixtureEl.setAttribute('id', fixtureId)
+    fixtureEl.style.display = 'none'
+    document.body.appendChild(fixtureEl)
+  }
+
+  return fixtureEl
+}
+
+export const clearFixture = () => {
+  const fixtureEl = getFixture()
+
+  fixtureEl.innerHTML = ''
+}