Use local Trino if available

Author: mdesmet

.github/DEVELOPMENT.md

@@ -42,7 +42,15 @@ To run integration tests:
 pytest tests/integration
 ```
 
-They pull a Docker image and then run a container with a Trino server:
+If you are already running a local Trino instance on the default port 8080, e.g.
+through`docker run -d -p 8080:8080  --name trino --rm trinodb/trino:latest`,
+the tests will automatically pick up this server instead of starting a new one
+on a random port. This is especially helpful for debugging purposes as you can
+inspect the executed queries through [the Trino web ui](http://localhost:8080/),
+it also saves you some time as the docker container won't have to be started.
+
+By default, the tests pull a Docker image and then run a container with a Trino 
+server:
 - the image is named `trinodb/trino:${TRINO_VERSION}`
 - the container is named `trino-python-client-tests-{uuid4()[:7]}`
 

tests/integration/conftest.py

@@ -31,6 +31,14 @@
 TRINO_PORT = 8080
 
 
+def is_trino_available():
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as sock:
+        sock.settimeout(2)
+        result = sock.connect_ex((TRINO_HOST, DEFAULT_PORT))
+        if result == 0:
+            return True
+
+
 def get_local_port():
     with closing(socket.socket()) as s:
         s.bind(("localhost", 0))
@@ -134,6 +142,10 @@ def stop_trino(container_id, proc):
 
 @pytest.fixture(scope="module")
 def run_trino():
+    if is_trino_available():
+        yield None, TRINO_HOST, DEFAULT_PORT
+        return
+
     image_tag = os.environ.get("TRINO_IMAGE")
     if not image_tag:
         image_tag = get_default_trino_image_tag()