--- a
+++ b/tests/lib/docker.py
@@ -0,0 +1,61 @@
+import os
+
+import docker
+from docker.errors import ContainerError, NotFound
+
+
+__all__ = ["ContainerError", "Containers"]
+
+
+class Containers:
+    def __init__(self):
+        self._docker = docker.from_env()
+
+    def get_engine_version(self):  # pragma: no cover
+        versions = self._docker.version()
+        engine_details = [c for c in versions["Components"] if c["Name"] == "Engine"]
+        assert len(engine_details) == 1
+        return engine_details[0]["Version"]
+
+    def get_container(self, name):
+        return self._docker.containers.get(name)
+
+    def is_running(self, name):
+        try:
+            container = self.get_container(name)
+            return container.status == "running"  # pragma: no cover
+        except NotFound:  # pragma: no cover
+            return False
+
+    def get_mapped_port_for_host(self, name, container_port):
+        """
+        Given a port on a container return the port on the host to which it is
+        mapped
+        """
+        container_port = f"{container_port}/tcp"
+        container = self.get_container(name)
+        port_config = container.attrs["NetworkSettings"]["Ports"][container_port]
+        host_port = port_config[0]["HostPort"]
+        return host_port
+
+    def get_container_ip(self, name):
+        """
+        Given a container name, return it IP address
+        """
+        container = self.get_container(name)
+        return container.attrs["NetworkSettings"]["IPAddress"]
+
+    # All available arguments documented here:
+    # https://docker-py.readthedocs.io/en/stable/containers.html#docker.models.containers.ContainerCollection.run
+    def run_bg(self, name, image, **kwargs):  # pragma: no cover
+        return self._run(name=name, image=image, detach=True, **kwargs)
+
+    # All available arguments documented here:
+    # https://docker-py.readthedocs.io/en/stable/containers.html#docker.models.containers.ContainerCollection.run
+    def run_captured(self, image, **kwargs):
+        return self._run(image=image, detach=False, stdout=True, stderr=True, **kwargs)
+
+    def _run(self, **kwargs):  # pragma: no cover
+        # Run as non-root by default to match production
+        kwargs.setdefault("user", os.getuid())
+        return self._docker.containers.run(remove=True, **kwargs)