feat testsuite: sync.wait_until()

commit_hash:5a66a1193a415700b1e66be8104fff80044e5c33

Author: segoon

.mapping.json

@@ -4785,6 +4785,7 @@
   "testsuite/pytest_plugins/pytest_userver/utils/__init__.py":"taxi/uservices/userver/testsuite/pytest_plugins/pytest_userver/utils/__init__.py",
   "testsuite/pytest_plugins/pytest_userver/utils/colorize.py":"taxi/uservices/userver/testsuite/pytest_plugins/pytest_userver/utils/colorize.py",
   "testsuite/pytest_plugins/pytest_userver/utils/net.py":"taxi/uservices/userver/testsuite/pytest_plugins/pytest_userver/utils/net.py",
+  "testsuite/pytest_plugins/pytest_userver/utils/sync.py":"taxi/uservices/userver/testsuite/pytest_plugins/pytest_userver/utils/sync.py",
   "testsuite/pytest_plugins/pytest_userver/utils/tskv.py":"taxi/uservices/userver/testsuite/pytest_plugins/pytest_userver/utils/tskv.py",
   "testsuite/requirements-grpc-3.txt":"taxi/uservices/userver/testsuite/requirements-grpc-3.txt",
   "testsuite/requirements-grpc-4.txt":"taxi/uservices/userver/testsuite/requirements-grpc-4.txt",

core/functional_tests/tracing/tests/conftest.py

@@ -1,6 +1,5 @@
-import asyncio
-
 import pytest
+import pytest_userver.utils.sync as sync
 
 pytest_plugins = ['pytest_userver.plugins.core']
 
@@ -67,7 +66,6 @@ async def _check_the_files(check_trace_id: str):
     records = capture.select(trace_id=trace_id)
     assert len(records) >= 1, capture.select()
 
-    retries = 100
     required_data = {
         f'\ttrace_id={trace_id}',
         'service_name=http-tracing-test',
@@ -81,7 +79,10 @@ async def _check_the_files(check_trace_id: str):
         '}]',
     }
 
-    for _ in range(retries):
+    probable_lines = []
+
+    async def check_ready() -> None:
+        nonlocal probable_lines
         probable_lines = []
         with open(jaeger_logs_path, 'r') as jaeger_file:
             for line in reversed(jaeger_file.read().split('\n')):
@@ -90,8 +91,11 @@ async def _check_the_files(check_trace_id: str):
 
                 if all(substr in line for substr in required_data):
                     return
+        raise sync.NotReady()
 
-        await asyncio.sleep(0.5)
-    assert False, (
-        f'Missing substrings {required_data} in opentracing file for trace id {trace_id}. Lines:\n {probable_lines}'
-    )
+    try:
+        await sync.wait_until(check_ready)
+    except TimeoutError:
+        assert False, (
+            f'Missing substrings {required_data} in opentracing file for trace id {trace_id}. Lines:\n {probable_lines}'
+        )

testsuite/pytest_plugins/pytest_userver/utils/sync.py

@@ -0,0 +1,47 @@
+import asyncio
+from collections.abc import Callable
+import datetime
+from typing import Any
+
+MAX_WAIT_TIME = datetime.timedelta(seconds=30)
+ITERATION_PERIOD_SECONDS = 0.5
+
+
+class NotReady(Exception):
+    pass
+
+
+async def wait_until(func: Callable) -> Any:
+    """
+    Waits for some external event for MAX_WAIT_TIME and
+    calls func every ITERATION_PERIOD_SECONDS.
+    If func raises NotReady exception, the waiting continues.
+    If func succesfully returns, wait_until() returns the same value.
+    After MAX_WAIT_TIME of unsuccesfull checks wait_until()
+    raises TimeoutError.
+
+    Example:
+
+    .. code-block:: python
+
+        async def try_to_connect_db():
+            if not db_conn_is_ok():
+                raise NotReady()
+
+        await wait_until(try_to_connect_db)
+
+    @throws TimeoutError after MAX_WAIT_TIME of unsuccesfull checks
+    @note If possible, use @ref testpoint instead. @ref testpoint is
+    an explicit message from the server "I'm ready", while wait_until()
+    uses an implicit idea "A condition is met, so I can continue".
+
+    @ingroup userver_testsuite
+    """
+    start = datetime.datetime.now()
+    while datetime.datetime.now() - start < MAX_WAIT_TIME:
+        try:
+            return await func()
+        except NotReady:
+            await asyncio.sleep(ITERATION_PERIOD_SECONDS)
+
+    raise TimeoutError()