__e2e_tests__/peerN-benchmark.js

+import { Selector } from "testcafe"
+
+const host = "127.0.0.1"
+const port = process.env.PORT || 3000
+
+const peerIndex = parseInt(process.env.PEER_INDEX)
+const numPeers = parseInt(process.env.NUM_PEERS)
+
+fixture`Peer ${peerIndex}`.page`${host}:${port}`
+
+const syncTimeout = numPeers * 1000
+const pollInterval = 500
+
+test(`Strokes from all peers should be rendered for peer ${peerIndex}`, async (t) => {
+  const canvas = Selector("#canvas").with({ timeout: 1000 })
+  await t.drag(canvas, 10 * peerIndex, 10)
+
+  let elapsed = 0
+  let syncComplete = false
+  for (; elapsed < syncTimeout; elapsed += pollInterval) {
+    if (await canvas.childElementCount == numPeers) {
+      syncComplete = true
+      break
+    }
+    await new Promise((resolve) => setTimeout(resolve, pollInterval))
+  }
+
+  if (syncComplete) {
+    console.log(
+      `Peer ${peerIndex}: Sync completed in ${elapsed}ms +- ${pollInterval}ms.`,
+    )
+  } else {
+    console.log(
+      `Peer ${peerIndex}: Sync failed, ${await canvas.childElementCount} out of ${numPeers} strokes were rendered before the ${syncTimeout}ms timeout.`,
+    )
+  }
+})