Add support for tmpfs mounting

Author: f18m

core/testcontainers/core/container.py

@@ -82,6 +82,8 @@ def __init__(
             for vol in volumes:
                 self.with_volume_mapping(*vol)
 
+        self.tmpfs: dict[str, str] = {}
+
         self.image = image
         self._docker = DockerClient(**(docker_client_kw or {}))
         self._container: Optional[Container] = None
@@ -198,6 +200,7 @@ def start(self) -> Self:
             ports=cast("dict[int, Optional[int]]", self.ports),
             name=self._name,
             volumes=self.volumes,
+            tmpfs=self.tmpfs,
             **{**network_kwargs, **self._kwargs},
         )
 
@@ -270,6 +273,16 @@ def with_volume_mapping(self, host: Union[str, PathLike[str]], container: str, m
         self.volumes[str(host)] = mapping
         return self
 
+    def with_tmpfs_mount(self, container_path: str, size: Optional[str] = None) -> Self:
+        """Mount a tmpfs volume on the container.
+        
+        :param container_path: Container path to mount tmpfs on (e.g., '/data')
+        :param size: Optional size limit (e.g., '256m', '1g'). If None, unbounded.
+        :return: Self for chaining
+        """
+        self.tmpfs[container_path] = size or ""
+        return self
+
     def get_wrapped_container(self) -> "Container":
         return self._container
 

modules/mqtt/testcontainers/mqtt/__init__.py

@@ -122,8 +122,8 @@ def start(self, configfile: Optional[str] = None) -> Self:
             configfile = Path(__file__).parent / MosquittoContainer.CONFIG_FILE
         self.with_volume_mapping(configfile, "/mosquitto/config/mosquitto.conf")
         # since version 2.1.1 - 2026-02-04, which fixed a PUID/PGID issue, the container needs to write to the data directory, 
-        # so we need to map it to a volume
-        self.with_volume_mapping("mosquitto_data", "/data", mode="rw")
+        # so we mount it as tmpfs for better performance in tests
+        self.with_tmpfs_mount("/data")
 
         # if self.password:
         #     # TODO: add authentication