feat: BaseEvalService declaration and surrounding data models

Also, adds a metric registry.

PiperOrigin-RevId: 778186012

tests/unittests/evaluation/test_metric_evaluator_registry.py

@@ -0,0 +1,92 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+from google.adk.errors.not_found_error import NotFoundError
+from google.adk.evaluation.eval_metrics import EvalMetric
+from google.adk.evaluation.evaluator import Evaluator
+from google.adk.evaluation.metric_evaluator_registry import MetricEvaluatorRegistry
+import pytest
+
+
+class TestMetricEvaluatorRegistry:
+  """Test cases for MetricEvaluatorRegistry."""
+
+  @pytest.fixture
+  def registry(self):
+    return MetricEvaluatorRegistry()
+
+  class DummyEvaluator(Evaluator):
+
+    def __init__(self, eval_metric: EvalMetric):
+      self._eval_metric = eval_metric
+
+    def evaluate_invocations(self, actual_invocations, expected_invocations):
+      return "dummy_result"
+
+  class AnotherDummyEvaluator(Evaluator):
+
+    def __init__(self, eval_metric: EvalMetric):
+      self._eval_metric = eval_metric
+
+    def evaluate_invocations(self, actual_invocations, expected_invocations):
+      return "another_dummy_result"
+
+  def test_register_evaluator(self, registry):
+    dummy_metric_name = "dummy_metric_name"
+    registry.register_evaluator(
+        dummy_metric_name,
+        TestMetricEvaluatorRegistry.DummyEvaluator,
+    )
+    assert dummy_metric_name in registry._registry
+    assert (
+        registry._registry[dummy_metric_name]
+        == TestMetricEvaluatorRegistry.DummyEvaluator
+    )
+
+  def test_register_evaluator_updates_existing(self, registry):
+    dummy_metric_name = "dummy_metric_name"
+    registry.register_evaluator(
+        dummy_metric_name,
+        TestMetricEvaluatorRegistry.DummyEvaluator,
+    )
+
+    assert (
+        registry._registry[dummy_metric_name]
+        == TestMetricEvaluatorRegistry.DummyEvaluator
+    )
+
+    registry.register_evaluator(
+        dummy_metric_name, TestMetricEvaluatorRegistry.AnotherDummyEvaluator
+    )
+    assert (
+        registry._registry[dummy_metric_name]
+        == TestMetricEvaluatorRegistry.AnotherDummyEvaluator
+    )
+
+  def test_get_evaluator(self, registry):
+    dummy_metric_name = "dummy_metric_name"
+    registry.register_evaluator(
+        dummy_metric_name,
+        TestMetricEvaluatorRegistry.DummyEvaluator,
+    )
+    eval_metric = EvalMetric(metric_name=dummy_metric_name, threshold=0.5)
+    evaluator = registry.get_evaluator(eval_metric)
+    assert isinstance(evaluator, TestMetricEvaluatorRegistry.DummyEvaluator)
+
+  def test_get_evaluator_not_found(self, registry):
+    eval_metric = EvalMetric(metric_name="non_existent_metric", threshold=0.5)
+    with pytest.raises(NotFoundError):
+      registry.get_evaluator(eval_metric)