diff --git a/src/pytest_celery/vendors/worker/volume.py b/src/pytest_celery/vendors/worker/volume.py
index eb144884..aa8b4a9f 100644
--- a/src/pytest_celery/vendors/worker/volume.py
+++ b/src/pytest_celery/vendors/worker/volume.py
@@ -21,7 +21,8 @@ def imports_src(self, modules: set[ModuleType]) -> dict:
                 src[f"{module.__name__.replace('.', '/')}.py"] = inspect.getsource(module).encode()
             return src
 
-        def app_name(self, name: str = DEFAULT_WORKER_APP_NAME) -> str:
+        def app_name(self, name: str | None = None) -> str:
+            name = name or DEFAULT_WORKER_APP_NAME
             return f"app = Celery('{name}')"
 
         def config(self, app: Celery | None = None) -> str:
@@ -47,17 +48,38 @@ def config(self, app: Celery | None = None) -> str:
                 config = "config = None"
             return config
 
-    def __init__(self) -> None:
+    def __init__(self, app_module: ModuleType | None = None) -> None:
         self.parser = self.Parser()
         self._initial_content = {
             "__init__.py": b"",
             "imports": dict(),
         }
+        self.set_app_module(app_module)
         self.set_app_name()
         self.set_config_from_object()
 
-    def set_app_module(self, app_module: ModuleType) -> None:
-        self._app_module_src = inspect.getsource(app_module)
+    def __eq__(self, __value: object) -> bool:
+        if not isinstance(__value, WorkerInitialContent):
+            return False
+        try:
+            return self.generate() == __value.generate()
+        except ValueError:
+            return all(
+                [
+                    self._app_module_src == __value._app_module_src,
+                    self._initial_content == __value._initial_content,
+                    self._app == __value._app,
+                    self._config == __value._config,
+                ]
+            )
+
+    def set_app_module(self, app_module: ModuleType | None = None) -> None:
+        self._app_module_src: str | None
+
+        if app_module:
+            self._app_module_src = inspect.getsource(app_module)
+        else:
+            self._app_module_src = None
 
     def add_modules(self, name: str, modules: set[ModuleType]) -> None:
         if not name:
@@ -69,15 +91,22 @@ def add_modules(self, name: str, modules: set[ModuleType]) -> None:
         self._initial_content["imports"][name] = self.parser.imports_str(modules)  # type: ignore
         self._initial_content.update(self.parser.imports_src(modules))
 
-    def set_app_name(self, name: str = DEFAULT_WORKER_APP_NAME) -> None:
+    def set_app_name(self, name: str | None = None) -> None:
+        name = name or DEFAULT_WORKER_APP_NAME
         self._app = self.parser.app_name(name)
 
     def set_config_from_object(self, app: Celery | None = None) -> None:
         self._config = self.parser.config(app)
 
     def generate(self) -> dict:
+        if not self._app_module_src:
+            raise ValueError("Please set_app_module() before calling generate()")
+
         initial_content = self._initial_content.copy()
 
+        if not initial_content["imports"]:
+            raise ValueError("Please add_modules() before calling generate()")
+
         _imports: dict | Any = initial_content.pop("imports")
         imports = "{%s}" % "}{".join(_imports.keys())
         imports = imports.format(**_imports)
diff --git a/tests/unit/vendors/test_worker/__init__.py b/tests/unit/vendors/test_worker/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/unit/vendors/test_worker/test_volume.py b/tests/unit/vendors/test_worker/test_volume.py
new file mode 100644
index 00000000..00568b0f
--- /dev/null
+++ b/tests/unit/vendors/test_worker/test_volume.py
@@ -0,0 +1,187 @@
+from __future__ import annotations
+
+import inspect
+from types import ModuleType
+
+import pytest
+from celery import Celery
+
+import pytest_celery
+from pytest_celery import DEFAULT_WORKER_APP_NAME
+from pytest_celery import WorkerInitialContent
+
+
+class test_worker_initial_content:
+    @pytest.mark.parametrize("parser", [WorkerInitialContent.Parser()])
+    class test_parser:
+        @pytest.mark.parametrize(
+            "modules",
+            [
+                set(),
+                {pytest},
+                {pytest, pytest_celery},
+            ],
+        )
+        class test_imports:
+            def test_imports_str(self, parser: WorkerInitialContent.Parser, modules: set[ModuleType]):
+                assert parser.imports_str(modules) == "".join(
+                    f"from {module.__name__} import *\n" for module in modules
+                )
+
+            def test_imports_src(self, parser: WorkerInitialContent.Parser, modules: set[ModuleType]):
+                assert parser.imports_src(modules) == {
+                    f"{module.__name__.replace('.', '/')}.py": inspect.getsource(module).encode() for module in modules
+                }
+
+        @pytest.mark.parametrize(
+            "name",
+            [
+                None,
+                "app",
+                "test_app",
+            ],
+        )
+        def test_app_name(self, parser: WorkerInitialContent.Parser, name: str):
+            assert parser.app_name(name) == f"app = Celery('{name or DEFAULT_WORKER_APP_NAME}')"
+
+        @pytest.mark.parametrize(
+            "app,config",
+            [
+                (None, None),
+                (Celery("test"), None),
+                (Celery(), {"broker_url": "420"}),
+            ],
+        )
+        def test_config(self, parser: WorkerInitialContent.Parser, app: Celery | None, config: dict | None):
+            if app and config:
+                app.conf.update(config)
+
+            if config:
+                changes = (f"\t{repr(key)}: {repr(value)}" for key, value in config.items())
+                expected_config = "config = {\n" + ",\n".join(changes) + "\n}" if changes else "config = None"
+            else:
+                expected_config = "config = None"
+
+            assert parser.config(app) == expected_config
+
+    def test_init(self):
+        actual_content = WorkerInitialContent()
+        assert isinstance(actual_content.parser, WorkerInitialContent.Parser)
+        assert actual_content._initial_content == {
+            "__init__.py": b"",
+            "imports": dict(),
+        }
+        assert actual_content._app == f"app = Celery('{DEFAULT_WORKER_APP_NAME}')"
+        assert actual_content._config == "config = None"
+
+    def test_eq(self):
+        from pytest_celery.vendors.worker import app as app_module
+
+        actual_content = WorkerInitialContent()
+
+        assert actual_content == WorkerInitialContent()
+        assert actual_content == actual_content
+
+        actual_content.set_app_module(app_module)
+        actual_content.add_modules("pytest", {pytest})
+        assert actual_content != WorkerInitialContent()
+
+    def test_set_app_module(self):
+        from pytest_celery.vendors.worker import app as app_module
+
+        actual_content = WorkerInitialContent()
+
+        actual_content.set_app_module(app_module)
+        assert actual_content._app_module_src == inspect.getsource(app_module)
+
+        actual_content.set_app_module(None)
+        assert actual_content._app_module_src is None
+
+    @pytest.mark.parametrize(
+        "modules",
+        [
+            {
+                "pytest": {pytest},
+            },
+            {
+                "pytest": {pytest},
+                "pytest_celery": {pytest_celery},
+            },
+            {
+                "pytest": {pytest, pytest_celery},
+                "pytest_celery": {pytest, pytest_celery},
+            },
+        ],
+    )
+    def test_add_modules(self, modules: dict[str, set[ModuleType]]):
+        from pytest_celery.vendors.worker import app as app_module
+
+        actual_content = WorkerInitialContent()
+
+        expected_content = WorkerInitialContent()
+        actual_content.set_app_module(app_module)
+        expected_content.set_app_module(app_module)
+
+        for module_name, module_set in modules.items():
+            actual_content.add_modules(module_name, module_set)
+
+        actual_intial_content = actual_content._initial_content
+        assert "imports" in actual_intial_content
+        assert modules.keys() == actual_intial_content["imports"].keys()
+
+        for module_name, modules_set in modules.items():
+            expected_content._initial_content["imports"][module_name] = actual_content.parser.imports_str(modules_set)
+            expected_content._initial_content.update(actual_content.parser.imports_src(modules_set))
+
+        assert actual_content == expected_content
+
+    def test_set_app_name(self):
+        actual_content = WorkerInitialContent()
+
+        actual_content.set_app_name()
+        assert actual_content._app == f"app = Celery('{DEFAULT_WORKER_APP_NAME}')"
+
+        actual_content.set_app_name("test")
+        assert actual_content._app == "app = Celery('test')"
+
+    def test_set_config_from_object(self):
+        actual_content = WorkerInitialContent()
+
+        actual_content.set_config_from_object()
+        assert actual_content._config == "config = None"
+
+        actual_content.set_config_from_object(Celery("test"))
+        assert actual_content._config == "config = None"
+
+        actual_content.set_config_from_object(Celery("test", broker_url="420"))
+        assert actual_content._config == "config = {\n\t'broker_url': '420'\n}"
+
+    class test_generate:
+        def test_generate_default(self):
+            actual_content = WorkerInitialContent()
+
+            with pytest.raises(ValueError):
+                actual_content.generate()
+
+        @pytest.mark.parametrize(
+            "app",
+            [
+                None,
+                Celery("test"),
+                Celery("test", broker_url="420"),
+            ],
+        )
+        def test_generate(self, app: Celery | None):
+            from pytest_celery.vendors.worker import app as app_module
+
+            actual_content = WorkerInitialContent()
+
+            actual_content.set_app_module(app_module)
+            actual_content.add_modules("tests_modules", {pytest, pytest_celery})
+            actual_content.set_config_from_object(app)
+
+            expected_content = WorkerInitialContent(app_module)
+            expected_content.add_modules("tests_modules", {pytest, pytest_celery})
+            expected_content.set_config_from_object(app)
+
+            assert actual_content.generate() == expected_content.generate()
diff --git a/tests/unit/vendors/test_worker.py b/tests/unit/vendors/test_worker/test_worker.py
similarity index 100%
rename from tests/unit/vendors/test_worker.py
rename to tests/unit/vendors/test_worker/test_worker.py