diff --git a/airbyte_cdk/sources/declarative/parsers/model_to_component_factory.py b/airbyte_cdk/sources/declarative/parsers/model_to_component_factory.py
index f6e1cc0d6..fbdf3e0de 100644
--- a/airbyte_cdk/sources/declarative/parsers/model_to_component_factory.py
+++ b/airbyte_cdk/sources/declarative/parsers/model_to_component_factory.py
@@ -1405,7 +1405,19 @@ def _get_class_from_fully_qualified_class_name(
         try:
             module_ref = importlib.import_module(module_name_full)
         except ModuleNotFoundError as e:
-            raise ValueError(f"Could not load module `{module_name_full}`.") from e
+            if split[0] == "source_declarative_manifest":
+                # During testing, the modules containing the custom components are not moved to source_declarative_manifest. In order to run the test, add the source folder to your PYTHONPATH or add it runtime using sys.path.append
+                try:
+                    import os
+
+                    module_name_with_source_declarative_manifest = ".".join(split[1:-1])
+                    module_ref = importlib.import_module(
+                        module_name_with_source_declarative_manifest
+                    )
+                except ModuleNotFoundError:
+                    raise ValueError(f"Could not load module `{module_name_full}`.") from e
+            else:
+                raise ValueError(f"Could not load module `{module_name_full}`.") from e
 
         try:
             return getattr(module_ref, class_name)
diff --git a/airbyte_cdk/sources/declarative/yaml_declarative_source.py b/airbyte_cdk/sources/declarative/yaml_declarative_source.py
index 04ccda4cf..a2a08f03b 100644
--- a/airbyte_cdk/sources/declarative/yaml_declarative_source.py
+++ b/airbyte_cdk/sources/declarative/yaml_declarative_source.py
@@ -39,13 +39,18 @@ def __init__(
         )
 
     def _read_and_parse_yaml_file(self, path_to_yaml_file: str) -> ConnectionDefinition:
-        package = self.__class__.__module__.split(".")[0]
+        try:
+            # For testing purposes, we want to allow to just pass a file
+            with open(path_to_yaml_file, "r") as f:
+                return yaml.safe_load(f)  # type: ignore  # we assume the yaml represents a ConnectionDefinition
+        except FileNotFoundError:
+            # Running inside the container, the working directory during an operation is not structured the same as the static files
+            package = self.__class__.__module__.split(".")[0]
 
-        yaml_config = pkgutil.get_data(package, path_to_yaml_file)
-        if yaml_config:
-            decoded_yaml = yaml_config.decode()
-            return self._parse(decoded_yaml)
-        else:
+            yaml_config = pkgutil.get_data(package, path_to_yaml_file)
+            if yaml_config:
+                decoded_yaml = yaml_config.decode()
+                return self._parse(decoded_yaml)
             return {}
 
     def _emit_manifest_debug_message(self, extra_args: dict[str, Any]) -> None: