feat(core): DockerCompose: support list of env_files (#847)

It is useful to be able to pass a list of `env_file`s, especially since
you can pass a list of `compose_file_name`s.
Builds upon
#135,
matching `compose_file_name`.

Author: mavcook

core/testcontainers/compose/compose.py

@@ -173,7 +173,7 @@ class DockerCompose:
             Wait for the services to be healthy
             (as per healthcheck definitions in the docker compose configuration)
         env_file:
-            Path to an '.env' file containing environment variables
+            Path(s) to an '.env' file containing environment variables
             to pass to docker compose.
         services:
             The list of services to use from this DockerCompose.
@@ -210,7 +210,7 @@ class DockerCompose:
     build: bool = False
     wait: bool = True
     keep_volumes: bool = False
-    env_file: Optional[str] = None
+    env_file: Optional[Union[str, list[str]]] = None
     services: Optional[list[str]] = None
     docker_command_path: Optional[str] = None
     profiles: Optional[list[str]] = None
@@ -219,6 +219,8 @@ class DockerCompose:
     def __post_init__(self) -> None:
         if isinstance(self.compose_file_name, str):
             self.compose_file_name = [self.compose_file_name]
+        if isinstance(self.env_file, str):
+            self.env_file = [self.env_file]
 
     def __enter__(self) -> "DockerCompose":
         self.start()
@@ -247,7 +249,8 @@ def compose_command_property(self) -> list[str]:
         if self.profiles:
             docker_compose_cmd += [item for profile in self.profiles for item in ["--profile", profile]]
         if self.env_file:
-            docker_compose_cmd += ["--env-file", self.env_file]
+            for env_file in self.env_file:
+                docker_compose_cmd += ["--env-file", env_file]
         return docker_compose_cmd
 
     def waiting_for(self, strategies: dict[str, WaitStrategy]) -> "DockerCompose":