Unit tests

test/docker_tests/test_docker_compose_unit.py

@@ -0,0 +1,41 @@
+import subprocess
+
+
+def test_run_docker_compose_returns_output(monkeypatch, tmp_path):
+    """Unit test that verifies `_run_docker_compose` returns a CompletedProcess
+    instance with an `output` attribute (combined stdout+stderr). This uses
+    monkeypatched subprocess.run to avoid invoking Docker.
+    """
+    from test.docker_tests import test_docker_compose_scenarios as mod
+
+    # Prepare a dummy compose file path
+    compose_file = tmp_path / "docker-compose.yml"
+    compose_file.write_text("services: {}")
+
+    # Prepare a sequence of CompletedProcess objects to be returned by fake `run`
+    cps = [
+        subprocess.CompletedProcess([], 0, stdout="down-initial\n", stderr=""),
+        subprocess.CompletedProcess(["up"], 0, stdout="up-out\n", stderr=""),
+        subprocess.CompletedProcess(["logs"], 0, stdout="log-out\n", stderr=""),
+        # ps_proc: cause compose ps parsing to fail (no containers listed)
+        subprocess.CompletedProcess(["ps"], 0, stdout="", stderr="no containers"),
+        subprocess.CompletedProcess([], 0, stdout="down-final\n", stderr=""),
+    ]
+
+    def fake_run(*args, **kwargs):
+        try:
+            return cps.pop(0)
+        except IndexError:
+            # Safety: return a harmless CompletedProcess
+            return subprocess.CompletedProcess([], 0, stdout="", stderr="")
+
+    # Monkeypatch subprocess.run used inside the module
+    monkeypatch.setattr(mod.subprocess, "run", fake_run)
+
+    # Call under test
+    result = mod._run_docker_compose(compose_file, "proj-test", timeout=1, detached=False)
+
+    # The returned object must have the combined `output` attribute
+    assert hasattr(result, "output")
+    assert "up-out" in result.output
+    assert "log-out" in result.output