Explicit tests for service method registering and inheritance (#556)

Per comments in #510 

- [x] Convert test classes to `MockService`
- [x] Add json schema support

mlos_bench/mlos_bench/config/schemas/services/mock-service-subschema.json

@@ -0,0 +1,21 @@
+{
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "$id": "https://raw.githubusercontent.com/microsoft/MLOS/main/mlos_bench/mlos_bench/config/schemas/services/mock-service-subschema.json",
+    "title": "mlos_bench Mock Service config",
+    "description": "config for an mlos_bench Mock Service",
+    "type": "object",
+    "properties": {
+        "class": {
+            "enum": [
+                "mlos_bench.tests.services.mock_service.MockServiceBase",
+                "mlos_bench.tests.services.mock_service.MockServiceChild"
+            ]
+        },
+        "config": {
+            "type": "object",
+            "$comment": "simple class for testing - no config properties accepted atm",
+            "unevaluatedProperties": false
+        }
+    },
+    "required": ["class"]
+}

mlos_bench/mlos_bench/config/schemas/services/service-schema.json

@@ -19,6 +19,9 @@
                         {
                             "$ref": "./local/temp-dir-context-service-subschema.json"
                         },
+                        {
+                            "$ref": "./mock-service-subschema.json"
+                        },
                         {
                             "$ref": "./local/mock/mock-local-exec-service-subschema.json"
                         },

mlos_bench/mlos_bench/tests/services/mock_service.py

@@ -0,0 +1,61 @@
+#
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+#
+"""
+Basic MockService for testing.
+
+See Also: test_service_method_registering.py
+"""
+
+from typing import Callable, Dict, List, Optional, Protocol, Union, runtime_checkable
+
+from mlos_bench.services.base_service import Service
+
+
+@runtime_checkable
+class SupportsSomeMethod(Protocol):
+    """Protocol for some_method"""
+
+    def some_method(self) -> str:
+        """some_method"""
+
+    def some_other_method(self) -> str:
+        """some_other_method"""
+
+
+class MockServiceBase(Service, SupportsSomeMethod):
+    """A base service class for testing."""
+
+    def __init__(
+            self,
+            config: Optional[dict] = None,
+            global_config: Optional[dict] = None,
+            parent: Optional[Service] = None,
+            methods: Optional[Union[Dict[str, Callable], List[Callable]]] = None) -> None:
+        super().__init__(
+            config,
+            global_config,
+            parent,
+            self.merge_methods(methods, [
+                self.some_method,
+                self.some_other_method,
+            ]))
+
+    def some_method(self) -> str:
+        """some_method"""
+        return f"{self}: base.some_method"
+
+    def some_other_method(self) -> str:
+        """some_other_method"""
+        return f"{self}: base.some_other_method"
+
+
+class MockServiceChild(MockServiceBase, SupportsSomeMethod):
+    """A child service class for testing."""
+
+    # Intentionally includes no constructor.
+
+    def some_method(self) -> str:
+        """some_method"""
+        return f"{self}: child.some_method"

mlos_bench/mlos_bench/tests/services/test_service_method_registering.py

@@ -0,0 +1,37 @@
+#
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+#
+"""
+Unit tests for Service method registering.
+"""
+
+from mlos_bench.services.base_service import Service
+
+from mlos_bench.tests.services.mock_service import SupportsSomeMethod, MockServiceBase, MockServiceChild
+
+
+def test_service_method_register_without_constructor() -> None:
+    """
+    Test registering a method without a constructor.
+    """
+    some_base_service = MockServiceBase()
+    some_child_service = MockServiceChild()
+
+    # create a mixin service that registers the base service methods
+    mixin_service = Service()
+    mixin_service.register(some_base_service.export())
+
+    # pylint complains if we try to just assert this directly
+    # somehow having it in a different scope makes a difference
+    if isinstance(mixin_service, SupportsSomeMethod):
+        assert mixin_service.some_method() == f"{some_base_service}: base.some_method"
+        assert mixin_service.some_other_method() == f"{some_base_service}: base.some_other_method"
+
+        # register the child service
+        mixin_service.register(some_child_service.export())
+        # check that the inheritance works as expected
+        assert mixin_service.some_method() == f"{some_child_service}: child.some_method"
+        assert mixin_service.some_other_method() == f"{some_child_service}: base.some_other_method"
+    else:
+        assert False