Testing: Add Testcontainer for MongoDB with improved configurability

It honors the `TC_KEEPALIVE` and `MONGODB_VERSION` environment
variables.

Defining `TC_KEEPALIVE` will set a signal not to shut down the container
after running the test cases, in order to speed up subsequent
invocations.

`MONGODB_VERSION` will define the designated MongoDB version, which is
useful when used within a test matrix. Its default value is `latest`.

cratedb_toolkit/testing/testcontainers/mongodb.py

@@ -0,0 +1,40 @@
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+import os
+
+from testcontainers.mongodb import MongoDbContainer
+
+from cratedb_toolkit.testing.testcontainers.util import KeepaliveContainer
+
+
+class MongoDbContainerWithKeepalive(KeepaliveContainer, MongoDbContainer):
+    """
+    A Testcontainer for MongoDB with improved configurability.
+
+    It honors the `TC_KEEPALIVE` and `MONGODB_VERSION` environment variables.
+
+    Defining `TC_KEEPALIVE` will set a signal not to shut down the container
+    after running the test cases, in order to speed up subsequent invocations.
+
+    `MONGODB_VERSION` will define the designated MongoDB version, which is
+    useful when used within a test matrix. Its default value is `latest`.
+    """
+
+    MONGODB_VERSION = os.environ.get("MONGODB_VERSION", "latest")
+
+    def __init__(
+        self,
+        image: str = f"mongo:{MONGODB_VERSION}",
+        **kwargs,
+    ) -> None:
+        super().__init__(image=image, **kwargs)