Harmonise container and improve error messages (#106)

* Harmonise mongodb container with other db containers.

* Improve error message for unstarted container (fixes #28).

Author: tillahoffmann

testcontainers/core/generic.py

@@ -29,12 +29,17 @@ def _connect(self):
     def get_connection_url(self):
         raise NotImplementedError
 
-    def _create_connection_url(self, dialect, username, password, port, db_name):
+    def _create_connection_url(self, dialect, username, password, port, db_name=None):
+        if self._container is None:
+            raise RuntimeError("container has not been started")
         host = self.get_container_host_ip()
         port = self.get_exposed_port(port)
-        return "{dialect}://{username}:{password}@{host}:{port}/{db}".format(
-            dialect=dialect, username=username, password=password, host=host, port=port, db=db_name
+        url = "{dialect}://{username}:{password}@{host}:{port}".format(
+            dialect=dialect, username=username, password=password, host=host, port=port
         )
+        if db_name:
+            url += '/' + db_name
+        return url
 
     def start(self):
         self._configure()

testcontainers/mongodb.py

@@ -12,10 +12,11 @@
 #    under the License.
 import os
 
-from testcontainers.core.generic import DockerContainer
+from testcontainers.core.generic import DbContainer
+from testcontainers.core.waiting_utils import wait_container_is_ready
 
 
-class MongoDbContainer(DockerContainer):
+class MongoDbContainer(DbContainer):
     """
     Mongo document-based database container.
 
@@ -55,22 +56,23 @@ def __init__(self, image="mongo:latest"):
         self.port_to_expose = 27017
         self.with_exposed_ports(self.port_to_expose)
 
-    def start(self):
-        self._configure()
-        super().start()
-        return self
-
     def _configure(self):
         self.with_env("MONGO_INITDB_ROOT_USERNAME", self.MONGO_INITDB_ROOT_USERNAME)
         self.with_env("MONGO_INITDB_ROOT_PASSWORD", self.MONGO_INITDB_ROOT_PASSWORD)
         self.with_env("MONGO_DB", self.MONGO_DB)
 
     def get_connection_url(self):
-        port = self.get_exposed_port(self.port_to_expose)
-        return "mongodb://{}:{}@{}:{}".format(self.MONGO_INITDB_ROOT_USERNAME,
-                                              self.MONGO_INITDB_ROOT_PASSWORD,
-                                              self.get_container_host_ip(), port)
+        return self._create_connection_url(
+            dialect='mongodb',
+            username=self.MONGO_INITDB_ROOT_USERNAME,
+            password=self.MONGO_INITDB_ROOT_PASSWORD,
+            port=self.port_to_expose,
+        )
 
-    def get_connection_client(self):
+    @wait_container_is_ready()
+    def _connect(self):
         from pymongo import MongoClient
         return MongoClient(self.get_connection_url())
+
+    def get_connection_client(self):
+        return self._connect()