Add semantic model test to test_contracts_graph_parsed.py

The tests in `test_contracts_graph_parsed.py` are meant to ensure
that we can go from objects to dictionaries and back without any
changes. We've had a desire to simplify these tests. Most tests in
this file have three to four fixtures, this test only has one. What
a test of this format ensures is that parsing a SemanticModel from
a dictionary doesn't add/drop any keys from the dictionary and that
when going back to the dictionary no keys are dropped. This style of
test will still break whenever the semantic model (or sub objects)
change. However now when that happens, only one fixture will have to
be updated (whereas previously we had to update 3-4 fixtures).

tests/unit/test_contracts_graph_parsed.py

@@ -34,6 +34,7 @@
     HookNode,
     Owner,
     TestMetadata,
+    SemanticModel,
 )
 from dbt.contracts.graph.unparsed import (
     ExposureType,
@@ -2354,3 +2355,111 @@ def basic_parsed_metric_object():
         meta={},
         tags=[],
     )
+
+
+# SEMANTIC MODELS
+
+
+@pytest.fixture
+def full_parsed_semantic_model_dict():
+    return {
+        # From BaseNode
+        "name": "full_parsed_semantic_model",
+        "resource_type": str(NodeType.SemanticModel),
+        "package_name": "semantic_models",
+        "path": "a_path",
+        "original_file_path": "where/it/lived",
+        "unique_id": "project_name.semantic_models.full_parsed_semantic_model",
+        # From GraphNode
+        "fqn": ["project_name", "semantic_models", "full_parsed_semantic_model"],
+        # From SemanticModel
+        "model": 'ref("model_name")',
+        "node_relation": {
+            "alias": "model_name",
+            "schema_name": "schema_name",
+            "database": "database_name",
+            "relation_name": "database_name.schema_name.model_name",
+        },
+        "description": "a description of what this semantic model represents",
+        "defaults": {"agg_time_dimension": "a_time_dimension_name"},
+        "entities": [
+            {
+                "name": "foreign_entity",
+                "type": "foreign",
+                "description": "id of foreign semantic model",
+                "role": "what is this",
+                "expr": "foreign_id",
+            }
+        ],
+        "measures": [
+            {
+                "name": "measuring_stuff",
+                "agg": "count",
+                "description": "a count of stuff",
+                "create_metric": True,
+                "expr": "1",
+                "agg_params": {
+                    "percentile": 0.5,
+                    "use_discrete_percentile": False,
+                    "use_approximate_percentile": False,
+                },
+                "non_additive_dimension": {
+                    "name": "dimension_name",
+                    "window_choice": "sum",
+                    "window_groupings": ["some", "groupings"],
+                },
+                "agg_time_dimension": "non_default_time_dimension",
+            }
+        ],
+        "dimensions": [
+            {
+                "name": "my_dimension",
+                "type": "categorical",
+                "description": "a dimension that denotes a category",
+                "is_partition": False,
+                "type_params": {
+                    "time_granularity": "day",
+                    "validity_params": {
+                        "is_start": False,
+                        "is_end": False,
+                    },
+                },
+                "expr": "column_name",
+                "metadata": {
+                    "repo_file_path": "where/it/lives/file.yml",
+                    "file_slice": {
+                        "filename": "file.yml",
+                        "content": "raw dimension yaml",
+                        "start_line_number": 25,
+                        "end_line_number": 30,
+                    },
+                },
+            }
+        ],
+        "metadata": {
+            "repo_file_path": "where/it/lived/file.yml",
+            "file_slice": {
+                "filename": "file.yml",
+                "content": "raw_yaml_object...",
+                "start_line_number": 15,
+                "end_line_number": 30,
+            },
+        },
+        "depends_on": {"macros": [], "nodes": []},
+        "refs": [],
+        "created_at": 1,
+        "config": {"enabled": False, "group": "my_group"},
+        "unrendered_config": {},
+        "primary_entity": "for_some_reason_i_set_this",
+        "group": "my_group",
+    }
+
+
+def test_full_parsed_semantic_model(full_parsed_semantic_model_dict):
+    # check that the object loaded from the dict is symmetric with the original dict
+    loaded_object = SemanticModel.from_dict(full_parsed_semantic_model_dict)
+    assert_symmetric(loaded_object, full_parsed_semantic_model_dict, SemanticModel)
+    assert_from_dict(loaded_object, full_parsed_semantic_model_dict, SemanticModel)
+
+    # check that the loaded_object can be dumped and loaded without error
+    pickle.loads(pickle.dumps(loaded_object))