chore: nit fixes (#441)

Author: pavelfeldman

playwright/_impl/_helper.py

@@ -150,7 +150,7 @@ def navigation_timeout(self) -> float:
 
 
 def serialize_error(ex: Exception, tb: Optional[TracebackType]) -> ErrorPayload:
-    return dict(message=str(ex), stack="".join(traceback.format_tb(tb)))
+    return dict(message=str(ex), name="Error", stack="".join(traceback.format_tb(tb)))
 
 
 def parse_error(error: ErrorPayload) -> Error:

playwright/_impl/_page.py

@@ -949,11 +949,13 @@ async def call(self, func: Callable) -> None:
             else:
                 func_args = list(map(parse_result, self._initializer["args"]))
                 result = func(source, *func_args)
-            if asyncio.isfuture(result):
+            if inspect.iscoroutine(result):
                 result = await result
             await self._channel.send("resolve", dict(result=serialize_argument(result)))
         except Exception as e:
             tb = sys.exc_info()[2]
             asyncio.create_task(
-                self._channel.send("reject", dict(error=serialize_error(e, tb)))
+                self._channel.send(
+                    "reject", dict(error=dict(error=serialize_error(e, tb)))
+                )
             )

tests/async/test_page.py

@@ -351,7 +351,7 @@ async def test_expose_function_should_await_returned_promise(page):
     async def mul(a, b):
         return a * b
 
-    await page.expose_function("compute", lambda a, b: asyncio.create_task(mul(a, b)))
+    await page.expose_function("compute", mul)
     assert await page.evaluate("compute(3, 5)") == 15