test: add reference count assertion script (#497)

Author: mxschmitt

.github/workflows/ci.yml

@@ -41,6 +41,8 @@ jobs:
           git diff
           exit 1
         fi
+    - name: Run reference checks
+      run: bash buildbots/test-reference-count.sh
   build:
     name: Build
     timeout-minutes: 30

buildbots/assets/test-reference-count-async.py

@@ -0,0 +1,45 @@
+import asyncio
+import gc
+
+import objgraph
+import pandas as pd
+
+from playwright.async_api import async_playwright
+
+
+def print_memory_objects() -> None:
+    gc.collect()
+
+    df_dicts = pd.DataFrame()
+    df_dicts["dicts"] = objgraph.by_type("dict")
+    df_dicts["pw_types"] = df_dicts["dicts"].apply(lambda x: x.get("_type"))
+
+    head = df_dicts["pw_types"].value_counts().head(20)
+
+    for class_name, reference_count in head.items():
+        print(class_name, reference_count)
+
+
+async def main() -> None:
+    async with async_playwright() as p:
+        browser = await p.chromium.launch()
+        page = await browser.new_page()
+        await page.goto("https://example.com")
+
+        page.on("dialog", lambda dialog: dialog.dismiss())
+        for _ in range(100):
+            await page.evaluate("""async () => alert()""")
+
+        await page.route("**/", lambda route, request: route.fulfill(body="OK"))
+
+        for i in range(100):
+            response = await page.evaluate("""async () => (await fetch("/")).text()""")
+            assert response == "OK"
+
+        await browser.close()
+    print_memory_objects()
+
+    print("PW-OK")
+
+
+asyncio.run(main())

buildbots/test-reference-count.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+set -e
+
+NOT_ALLOWED_REFERENCES=("Dialog" "Request" "Route")
+
+OUTPUT=$(python buildbots/assets/test-reference-count-async.py)
+
+if [[ "$OUTPUT" != *"PW-OK"* ]]; then
+  echo "Script did not run successfully!"
+  echo "Output: $OUTPUT"
+  exit 1
+fi
+
+for CLASS_NAME in ${NOT_ALLOWED_REFERENCES[*]}; do
+  echo "Checking $CLASS_NAME"
+  if [[ "$OUTPUT" == *"$CLASS_NAME"* ]]; then
+    echo "There are $CLASS_NAME references in the memory!"
+    echo "Output: $OUTPUT"
+    exit 1
+  fi
+  echo "Check $CLASS_NAME passed"
+done
+
+echo "-> Reference count assertions passed!"

local-requirements.txt

@@ -19,3 +19,5 @@ flake8==3.8.3
 twine==3.2.0
 pyOpenSSL==19.1.0
 service_identity==18.1.0
+pandas==1.2.2
+objgraph==3.5.0