test: add isolated Nginx HTTP2 upstream and rolling drain checks

scripts/verifyHTTP2Proxy_test.py

@@ -0,0 +1,59 @@
+"""Keep proxy integration failures and interrupts inside their resource envelope."""
+
+import importlib.util
+import io
+from pathlib import Path
+import subprocess
+import time
+import unittest
+from unittest.mock import patch
+
+
+spec = importlib.util.spec_from_file_location("proxyRunner", Path(__file__).with_name("verifyHTTP2Proxy.py"))
+runnerModule = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(runnerModule)
+
+
+class ContainerCleanupTests(unittest.TestCase):
+    def testFailedAndInterruptedStagesRemoveOnlyTheirContainer(self):
+        failures = (subprocess.TimeoutExpired("docker", 1), KeyboardInterrupt(), subprocess.CompletedProcess([], 7))
+        for failure in failures:
+            with self.subTest(failure=type(failure).__name__):
+                calls = []
+
+                def execute(command, **kwargs):
+                    calls.append(command)
+                    if command[1] == "run":
+                        if isinstance(failure, BaseException):
+                            raise failure
+                        return failure
+                    return subprocess.CompletedProcess(command, 0, "", "")
+
+                runner = runnerModule.ContainerRunner("/fake/docker", io.StringIO(), time.monotonic() + 10)
+                with patch.object(runnerModule.subprocess, "run", side_effect=execute):
+                    with self.assertRaises((subprocess.TimeoutExpired, KeyboardInterrupt, RuntimeError)):
+                        runner.container("owned-proxy-check", ["nginx:test"])
+                self.assertEqual(calls[1:], [["/fake/docker", "rm", "--force", "owned-proxy-check"]])
+                self.assertEqual(runner.cleaned, ["owned-proxy-check"])
+
+    def testCleanupFailureRemainsAnError(self):
+        runner = runnerModule.ContainerRunner("/fake/docker", io.StringIO(), time.monotonic() + 10)
+        with patch.object(runnerModule.subprocess, "run", side_effect=[
+            subprocess.CompletedProcess([], 0),
+            subprocess.CompletedProcess([], 1, "", "Docker daemon unavailable"),
+        ]):
+            with self.assertRaisesRegex(RuntimeError, "could not clean up"):
+                runner.container("owned-proxy-check", ["nginx:test"])
+        self.assertEqual(runner.cleaned, [])
+
+    def testDeadlinePreventsStartingAnotherContainer(self):
+        runner = runnerModule.ContainerRunner("/fake/docker", io.StringIO(), time.monotonic() - 1)
+        with patch.object(runnerModule.subprocess, "run", return_value=subprocess.CompletedProcess([], 0, "", "")) as execute:
+            with self.assertRaises(TimeoutError):
+                runner.container("not-started", ["nginx:test"])
+        self.assertEqual(execute.call_args.args[0], ["/fake/docker", "rm", "--force", "not-started"])
+        self.assertEqual(execute.call_count, 1)
+
+
+if __name__ == "__main__":
+    unittest.main()