diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..bce9977
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,19 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  checks:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+      - uses: actions/setup-python@v7
+        with:
+          python-version: "3.12"
+      - run: pip install -e ".[dev]"
+      - run: ruff check .
+      - run: ruff format --check .
+      - run: pytest -q
diff --git a/tests/test_client_create.py b/tests/test_client_create.py
index 38bec93..f81fc01 100644
--- a/tests/test_client_create.py
+++ b/tests/test_client_create.py
@@ -156,3 +156,13 @@ def test_rollback_hard_failure_is_reported_as_failed():
     assert error.states == {A: PRESENT, B: ABSENT, C: ABSENT}
     assert error.cluster_consistent is False
     assert str(error).endswith("rollback: http://b restored, http://a failed")
+
+
+def test_context_manager_closes_only_the_http_client_it_created():
+    shared = httpx.Client(transport=httpx.MockTransport(lambda request: httpx.Response(404)))
+    with ClusterClient(["node1"], client=shared):
+        pass
+    assert not shared.is_closed
+    with ClusterClient(["node1"]) as owned:
+        pass
+    assert owned._client.is_closed
diff --git a/tests/test_drive.py b/tests/test_drive.py
index 847eab8..2d93387 100644
--- a/tests/test_drive.py
+++ b/tests/test_drive.py
@@ -4,7 +4,7 @@
 import pytest
 
 from api_consumer.node_api import NodeState
-from api_consumer.retry import drive_node_to
+from api_consumer.retry import RetryPolicy, drive_node_to
 from fake_cluster import FakeCluster, recording_policy
 
 PRESENT, ABSENT, UNKNOWN = NodeState.PRESENT, NodeState.ABSENT, NodeState.UNKNOWN
@@ -101,3 +101,9 @@ def test_delete_timeout_then_get_absent_is_success_with_no_second_delete():
     result, calls, _ = drive(ABSENT, mutations=[TIMEOUT], gets=[404])
     assert (result.reached, result.state) == (True, ABSENT)
     assert calls == ["DELETE", "GET"]
+
+
+def test_a_policy_without_attempts_is_rejected():
+    node = FakeCluster().node("node1")
+    with pytest.raises(ValueError):
+        drive_node_to(node, "g1", PRESENT, RetryPolicy(max_attempts=0, sleep=lambda _: None))
diff --git a/tests/test_node_api.py b/tests/test_node_api.py
index b758286..da3acc9 100644
--- a/tests/test_node_api.py
+++ b/tests/test_node_api.py
@@ -64,6 +64,7 @@ def test_get_404_means_absent():
         respond(200, {"groupId": "other"}),
         respond(200, {"x": 1}),
         respond(200, [1]),
+        lambda request: httpx.Response(200, text="not json"),
         respond(204),
         respond(403),
     ],