[CT-2879] Fix unbound variable error in `checked_agg_time_dimension_f…

…or_measure` (#8235) (#8240)

* Fix unbound variable error in `checked_agg_time_dimension_for_measure`

* Improve assertion error message in `checked_agg_time_dimension_for_measure`

* Add changie doc for checked_agg_time_dimension_for_measure unbound variable fix

* Add unit tests for checking functionality of `checked_agg_time_dimension_for_measure`

Co-authored-by: Emily Rockman <emily.rockman@dbtlabs.com>

.changes/unreleased/Fixes-20230727-125830.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Fix unbound local variable error in `checked_agg_time_dimension_for_measure`
+time: 2023-07-27T12:58:30.673803-07:00
+custom:
+  Author: QMalcolm
+  Issue: "8230"

core/dbt/contracts/graph/nodes.py

@@ -1568,14 +1568,15 @@ def checked_agg_time_dimension_for_measure(
             measure is not None
         ), f"No measure with name ({measure_reference.element_name}) in semantic_model with name ({self.name})"
 
-        if self.defaults is not None:
-            default_agg_time_dimesion = self.defaults.agg_time_dimension
+        default_agg_time_dimension = (
+            self.defaults.agg_time_dimension if self.defaults is not None else None
+        )
 
-        agg_time_dimension_name = measure.agg_time_dimension or default_agg_time_dimesion
+        agg_time_dimension_name = measure.agg_time_dimension or default_agg_time_dimension
         assert agg_time_dimension_name is not None, (
-            f"Aggregation time dimension for measure {measure.name} is not set! This should either be set directly on "
-            f"the measure specification in the model, or else defaulted to the primary time dimension in the data "
-            f"source containing the measure."
+            f"Aggregation time dimension for measure {measure.name} on semantic model {self.name} is not set! "
+            "To fix this either specify a default `agg_time_dimension` for the semantic model or define an "
+            "`agg_time_dimension` on the measure directly."
         )
         return TimeDimensionReference(element_name=agg_time_dimension_name)
 

tests/unit/test_semantic_models.py

@@ -0,0 +1,81 @@
+import pytest
+
+from typing import List
+
+from dbt.contracts.graph.nodes import SemanticModel
+from dbt.contracts.graph.semantic_models import Dimension, Entity, Measure, Defaults
+from dbt.node_types import NodeType
+from dbt_semantic_interfaces.references import MeasureReference
+from dbt_semantic_interfaces.type_enums import AggregationType, DimensionType, EntityType
+
+
+@pytest.fixture(scope="function")
+def dimensions() -> List[Dimension]:
+    return [Dimension(name="ds", type=DimensionType)]
+
+
+@pytest.fixture(scope="function")
+def entities() -> List[Entity]:
+    return [Entity(name="test_entity", type=EntityType.PRIMARY, expr="id")]
+
+
+@pytest.fixture(scope="function")
+def measures() -> List[Measure]:
+    return [Measure(name="test_measure", agg=AggregationType.COUNT, expr="id")]
+
+
+@pytest.fixture(scope="function")
+def default_semantic_model(
+    dimensions: List[Dimension], entities: List[Entity], measures: List[Measure]
+) -> SemanticModel:
+    return SemanticModel(
+        name="test_semantic_model",
+        resource_type=NodeType.SemanticModel,
+        model="ref('test_model')",
+        package_name="test",
+        path="test_path",
+        original_file_path="test_fixture",
+        unique_id=f"{NodeType.SemanticModel}.test.test_semantic_model",
+        fqn=[],
+        defaults=Defaults(agg_time_dimension="ds"),
+        dimensions=dimensions,
+        entities=entities,
+        measures=measures,
+        node_relation=None,
+    )
+
+
+def test_checked_agg_time_dimension_for_measure_via_defaults(
+    default_semantic_model: SemanticModel,
+):
+    assert default_semantic_model.defaults.agg_time_dimension is not None
+    measure = default_semantic_model.measures[0]
+    measure.agg_time_dimension = None
+    default_semantic_model.checked_agg_time_dimension_for_measure(
+        MeasureReference(element_name=measure.name)
+    )
+
+
+def test_checked_agg_time_dimension_for_measure_via_measure(default_semantic_model: SemanticModel):
+    default_semantic_model.defaults = None
+    measure = default_semantic_model.measures[0]
+    measure.agg_time_dimension = default_semantic_model.dimensions[0].name
+    default_semantic_model.checked_agg_time_dimension_for_measure(
+        MeasureReference(element_name=measure.name)
+    )
+
+
+def test_checked_agg_time_dimension_for_measure_exception(default_semantic_model: SemanticModel):
+    default_semantic_model.defaults = None
+    measure = default_semantic_model.measures[0]
+    measure.agg_time_dimension = None
+
+    with pytest.raises(AssertionError) as execinfo:
+        default_semantic_model.checked_agg_time_dimension_for_measure(
+            MeasureReference(measure.name)
+        )
+
+    assert (
+        f"Aggregation time dimension for measure {measure.name} on semantic model {default_semantic_model.name}"
+        in str(execinfo.value)
+    )