diff --git a/core/tests/common.py b/core/tests/common.py
index 1e699e3820..fce79b33c1 100644
--- a/core/tests/common.py
+++ b/core/tests/common.py
@@ -1,9 +1,23 @@
 import sys
 
-sys.path.append('../src')
+sys.path.append("../src")
 
 from ubinascii import hexlify, unhexlify  # noqa: F401
 
 import unittest  # noqa: F401
 
 from trezor import utils  # noqa: F401
+
+
+def await_result(task: Awaitable) -> Any:
+    value = None
+    while True:
+        try:
+            result = task.send(value)
+        except StopIteration as e:
+            return e.value
+
+        if result:
+            value = await_result(result)
+        else:
+            value = None
diff --git a/core/tests/test_protobuf.py b/core/tests/test_protobuf.py
index d362401e52..c6de123319 100644
--- a/core/tests/test_protobuf.py
+++ b/core/tests/test_protobuf.py
@@ -44,28 +44,14 @@ class ByteArrayWriter:
         return len(buf)
 
 
-def run_until_complete(task: Awaitable) -> Any:
-    value = None
-    while True:
-        try:
-            result = task.send(value)
-        except StopIteration as e:
-            return e.value
-
-        if result:
-            value = run_until_complete(result)
-        else:
-            value = None
-
-
 def load_uvarint(data: bytes) -> int:
     reader = ByteReader(data)
-    return run_until_complete(protobuf.load_uvarint(reader))
+    return await_result(protobuf.load_uvarint(reader))
 
 
 def dump_uvarint(value: int) -> bytearray:
     writer = ByteArrayWriter()
-    run_until_complete(protobuf.dump_uvarint(writer, value))
+    await_result(protobuf.dump_uvarint(writer, value))
     return writer.buf
 
 
@@ -106,9 +92,9 @@ class TestProtobuf(unittest.TestCase):
         # ok message:
         msg = Message(-42, 5)
         writer = ByteArrayWriter()
-        run_until_complete(protobuf.dump_message(writer, msg))
+        await_result(protobuf.dump_message(writer, msg))
         reader = ByteReader(bytes(writer.buf))
-        nmsg = run_until_complete(protobuf.load_message(reader, Message))
+        nmsg = await_result(protobuf.load_message(reader, Message))
 
         self.assertEqual(msg.sint_field, nmsg.sint_field)
         self.assertEqual(msg.enum_field, nmsg.enum_field)
@@ -116,10 +102,10 @@ class TestProtobuf(unittest.TestCase):
         # bad enum value:
         msg = Message(-42, 42)
         writer = ByteArrayWriter()
-        run_until_complete(protobuf.dump_message(writer, msg))
+        await_result(protobuf.dump_message(writer, msg))
         reader = ByteReader(bytes(writer.buf))
         with self.assertRaises(TypeError):
-            run_until_complete(protobuf.load_message(reader, Message))
+            await_result(protobuf.load_message(reader, Message))
 
 
 if __name__ == "__main__":