Adds test that all constructors and purposes are tested and that they…

… all share the same signature (#2764)

Summary:
Pull Request resolved: #2764

This is a requested follow up by Liz/Sait/Daniel to (1) ensure all constructor methods share the same signature and (2) ensure that they are all tested.

For two, this still relies on best effort to ensure that when you add a new constructor you actually add the relevant tests, but it will ensure that the new constructor has the correct signature.

These input constructors are more simple than those used in the modeling layer so i do believe they should be less error prone generally

Follow up diffs:
- storage for input constructors --> let's do this once we all like the 3 input constructors
- update the input constructors to handle the case where n isn't provided as a kwarg
- decide if it's more legible for the circular import avoider to be on inputconstructors instead of the generationnode file

Reviewed By: lena-kashtelyan

Differential Revision: D62553827

fbshipit-source-id: d1eddb4038e96f39fdc98dfa1a73ef0c29e528a4

ax/modelbridge/generation_node_input_constructors.py

@@ -109,6 +109,8 @@ def remaining_n(
 class NodeInputConstructors(Enum):
     """An enum which maps to a callable method for constructing ``GenerationNode``
     inputs.
+
+    NOTE: The methods defined by this enum should all share identical signatures.
     """
 
     ALL_N = consume_all_n

ax/modelbridge/tests/test_generation_node_input_constructors.py

@@ -5,10 +5,17 @@
 
 # pyre-strict
 
+import inspect
+from collections import Counter
+from typing import Any, Dict, get_type_hints, Optional
+
 from ax.core.arm import Arm
 from ax.core.generator_run import GeneratorRun
 from ax.modelbridge.generation_node import GenerationNode
-from ax.modelbridge.generation_node_input_constructors import NodeInputConstructors
+from ax.modelbridge.generation_node_input_constructors import (
+    InputConstructorPurpose,
+    NodeInputConstructors,
+)
 from ax.modelbridge.model_spec import ModelSpec
 from ax.modelbridge.registry import Models
 from ax.utils.common.testutils import TestCase
@@ -126,3 +133,40 @@ def test_no_n_provided_error_remaining_n(self) -> None:
                 next_node=self.sobol_generation_node,
                 gs_gen_call_kwargs={},
             )
+
+
+class TestInstantiationFromNodeInputConstructor(TestCase):
+    """Class to test that all node input constructors can be instantiated and are
+    being tested."""
+
+    def setUp(self) -> None:
+        super().setUp()
+        self.constructor_cases = {
+            "ALl_N": NodeInputConstructors.ALL_N,
+            "REPEAT_N": NodeInputConstructors.REPEAT_N,
+            "REMAINING_N": NodeInputConstructors.REMAINING_N,
+        }
+        self.purpose_cases = {
+            "N": InputConstructorPurpose.N,
+        }
+
+    def test_all_constructors_have_same_signature(self) -> None:
+        """Test that all node input constructors methods have the same signature
+        and that the parameters are of the expected types"""
+        all_constructors_tested = list(self.constructor_cases.values())
+        method_signature = inspect.signature(all_constructors_tested[0])
+        for constructor in all_constructors_tested[1:]:
+            with self.subTest(constructor=constructor):
+                func_parameters = get_type_hints(constructor)
+                self.assertEqual(
+                    Counter(list(func_parameters.keys())),
+                    Counter(
+                        ["previous_node", "next_node", "gs_gen_call_kwargs", "return"]
+                    ),
+                )
+                self.assertEqual(
+                    func_parameters["previous_node"], Optional[GenerationNode]
+                )
+                self.assertEqual(func_parameters["next_node"], GenerationNode)
+                self.assertEqual(func_parameters["gs_gen_call_kwargs"], Dict[str, Any])
+                self.assertEqual(method_signature, inspect.signature(constructor))