Fix rendering dbt tests with multiple parents

cosmos/airflow/graph.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from collections import defaultdict
 from typing import Any, Callable, Union
 
 from airflow.models import BaseOperator
@@ -74,6 +75,26 @@ def calculate_leaves(tasks_ids: list[str], nodes: dict[str, DbtNode]) -> list[st
     return leaves
 
 
+def exclude_detached_tests_if_needed(
+    node: DbtNode,
+    task_args: dict[str, str],
+    detached_from_parent: dict[str, DbtNode] | None = None,
+) -> None:
+    """
+    Add exclude statements if there are tests associated to the model that should be run detached from the model/tests.
+
+    Change task_args in-place.
+    """
+    if detached_from_parent is None:
+        detached_from_parent = {}
+    exclude: list[str] = task_args.get("exclude", [])  # type: ignore
+    tests_detached_from_this_node: list[DbtNode] = detached_from_parent.get(node.unique_id, [])  # type: ignore
+    for test_node in tests_detached_from_this_node:
+        exclude.append(test_node.resource_name.split(".")[0])
+    if exclude:
+        task_args["exclude"] = exclude  # type: ignore
+
+
 def create_test_task_metadata(
     test_task_name: str,
     execution_mode: ExecutionMode,
@@ -82,6 +103,7 @@ def create_test_task_metadata(
     on_warning_callback: Callable[..., Any] | None = None,
     node: DbtNode | None = None,
     render_config: RenderConfig | None = None,
+    detached_from_parent: dict[str, DbtNode] | None = None,
 ) -> TaskMetadata:
     """
     Create the metadata that will be used to instantiate the Airflow Task that will be used to run the Dbt test node.
@@ -92,11 +114,13 @@ def create_test_task_metadata(
     :param on_warning_callback: A callback function called on warnings with additional Context variables “test_names”
     and “test_results” of type List.
     :param node: If the test relates to a specific node, the node reference
+    :param detached_from_parent: Dictionary that maps node ids and their children tests that should be run detached
     :returns: The metadata necessary to instantiate the source dbt node as an Airflow task.
     """
     task_args = dict(task_args)
     task_args["on_warning_callback"] = on_warning_callback
     extra_context = {}
+    detached_from_parent = detached_from_parent or {}
 
     task_owner = ""
     airflow_task_config = {}
@@ -119,6 +143,9 @@ def create_test_task_metadata(
         task_args["selector"] = render_config.selector
         task_args["exclude"] = render_config.exclude
 
+    if node:
+        exclude_detached_tests_if_needed(node, task_args, detached_from_parent)
+
     return TaskMetadata(
         id=test_task_name,
         owner=task_owner,
@@ -192,6 +219,7 @@ def create_task_metadata(
     normalize_task_id: Callable[..., Any] | None = None,
     test_behavior: TestBehavior = TestBehavior.AFTER_ALL,
     on_warning_callback: Callable[..., Any] | None = None,
+    detached_from_parent: dict[str, DbtNode] | None = None,
 ) -> TaskMetadata | None:
     """
     Create the metadata that will be used to instantiate the Airflow Task used to run the Dbt node.
@@ -205,6 +233,7 @@ def create_task_metadata(
         If it is False, then use the name as a prefix for the task id, otherwise do not.
     :param on_warning_callback: A callback function called on warnings with additional Context variables “test_names”
         and “test_results” of type List. This is param available for dbt test and dbt source freshness command.
+    :param detached_from_parent: Dictionary that maps node ids and their children tests that should be run detached
     :returns: The metadata necessary to instantiate the source dbt node as an Airflow task.
     """
     dbt_resource_to_class = create_dbt_resource_to_class(test_behavior)
@@ -218,6 +247,7 @@ def create_task_metadata(
         }
 
         if test_behavior == TestBehavior.BUILD and node.resource_type in SUPPORTED_BUILD_RESOURCES:
+            exclude_detached_tests_if_needed(node, args, detached_from_parent)
             task_id, args = _get_task_id_and_args(
                 node, args, use_task_group, normalize_task_id, "build", include_resource_type=True
             )
@@ -268,6 +298,17 @@ def create_task_metadata(
         return None
 
 
+def is_detached_test(node: DbtNode) -> bool:
+    """
+    Identify if node should be rendered detached from the parent. Conditions that should be met:
+    * is a test
+    * has multiple parents
+    """
+    if node.resource_type == DbtResourceType.TEST and len(node.depends_on) > 1:
+        return True
+    return False
+
+
 def generate_task_or_group(
     dag: DAG,
     task_group: TaskGroup | None,
@@ -279,9 +320,11 @@ def generate_task_or_group(
     test_indirect_selection: TestIndirectSelection,
     on_warning_callback: Callable[..., Any] | None,
     normalize_task_id: Callable[..., Any] | None = None,
+    detached_from_parent: dict[str, DbtNode] | None = None,
     **kwargs: Any,
 ) -> BaseOperator | TaskGroup | None:
     task_or_group: BaseOperator | TaskGroup | None = None
+    detached_from_parent = detached_from_parent or {}
 
     use_task_group = (
         node.resource_type in TESTABLE_DBT_RESOURCES
@@ -299,12 +342,13 @@ def generate_task_or_group(
         normalize_task_id=normalize_task_id,
         test_behavior=test_behavior,
         on_warning_callback=on_warning_callback,
+        detached_from_parent=detached_from_parent,
     )
 
     # In most cases, we'll  map one DBT node to one Airflow task
     # The exception are the test nodes, since it would be too slow to run test tasks individually.
     # If test_behaviour=="after_each", each model task will be bundled with a test task, using TaskGroup
-    if task_meta and node.resource_type != DbtResourceType.TEST:
+    if task_meta and not node.resource_type == DbtResourceType.TEST:
         if use_task_group:
             with TaskGroup(dag=dag, group_id=node.name, parent_group=task_group) as model_task_group:
                 task = create_airflow_task(task_meta, dag, task_group=model_task_group)
@@ -315,12 +359,14 @@ def generate_task_or_group(
                     task_args=task_args,
                     node=node,
                     on_warning_callback=on_warning_callback,
+                    detached_from_parent=detached_from_parent,
                 )
                 test_task = create_airflow_task(test_meta, dag, task_group=model_task_group)
                 task >> test_task
                 task_or_group = model_task_group
         else:
             task_or_group = create_airflow_task(task_meta, dag, task_group=task_group)
+
     return task_or_group
 
 
@@ -405,6 +451,16 @@ def build_airflow_graph(
     tasks_map: dict[str, Union[TaskGroup, BaseOperator]] = {}
     task_or_group: TaskGroup | BaseOperator
 
+    # Identify test nodes that should be run detached from the associated dbt resource nodes because they
+    # have multiple parents
+    detached_from_parent = defaultdict(list)
+    detached_nodes = {}
+    for node_id, node in nodes.items():
+        if is_detached_test(node):
+            detached_nodes[node_id] = node
+            for parent_id in node.depends_on:
+                detached_from_parent[parent_id].append(node)
+
     for node_id, node in nodes.items():
         conversion_function = node_converters.get(node.resource_type, generate_task_or_group)
         if conversion_function != generate_task_or_group:
@@ -425,11 +481,26 @@ def build_airflow_graph(
             on_warning_callback=on_warning_callback,
             normalize_task_id=normalize_task_id,
             node=node,
+            detached_from_parent=detached_from_parent,
         )
         if task_or_group is not None:
             logger.debug(f"Conversion of <{node.unique_id}> was successful!")
             tasks_map[node_id] = task_or_group
 
+    # Handle detached test nodes
+    for node_id, node in detached_nodes.items():
+        test_meta = create_test_task_metadata(
+            f"{node.resource_name.split('.')[0]}_test",
+            execution_mode,
+            test_indirect_selection,
+            task_args=task_args,
+            on_warning_callback=on_warning_callback,
+            render_config=render_config,
+            node=node,
+        )
+        test_task = create_airflow_task(test_meta, dag, task_group=task_group)
+        tasks_map[node_id] = test_task
+
     # If test_behaviour=="after_all", there will be one test task, run by the end of the DAG
     # The end of a DAG is defined by the DAG leaf tasks (tasks which do not have downstream tasks)
     if test_behavior == TestBehavior.AFTER_ALL:

dev/dags/dbt/jaffle_shop/models/schema.yml

@@ -39,13 +39,14 @@ models:
           - not_null
         description: This is a unique identifier for an order
 
-      - name: customer_id
-        description: Foreign key to the customers table
-        tests:
-          - not_null
-          - relationships:
-              to: ref('customers')
-              field: customer_id
+      # Comment so we don't have a standalone test relationships_orders_customer_id__customer_id__ref_customers__test
+      #- name: customer_id
+      #  description: Foreign key to the customers table
+      #  tests:
+      #    - not_null
+      #    - relationships:
+      #        to: ref('customers')
+      #        field: customer_id
 
       - name: order_date
         description: Date (UTC) that the order was placed

dev/dags/dbt/multiple_parents_test/dbt_project.yml

@@ -0,0 +1,12 @@
+name: 'my_dbt_project'
+version: '1.0.0'
+config-version: 2
+
+profile: 'default'
+
+model-paths: ["models"]
+test-paths: ["tests"]
+
+models:
+  my_dbt_project:
+    materialized: view

dev/dags/dbt/multiple_parents_test/macros/custom_test_combined_model.sql

@@ -0,0 +1,17 @@
+{% test custom_test_combined_model(model) %}
+WITH source_data AS (
+    SELECT id FROM {{ ref('model_a') }}
+),
+combined_data AS (
+    SELECT id FROM {{ model }}
+)
+SELECT
+    s.id
+FROM
+    source_data s
+LEFT JOIN
+    combined_data c
+    ON s.id = c.id
+WHERE
+    c.id IS NULL
+{% endtest %}

dev/dags/dbt/multiple_parents_test/models/combined_model.sql

@@ -0,0 +1,16 @@
+-- Combine data from model_a and model_b
+WITH model_a AS (
+    SELECT * FROM {{ ref('model_a') }}
+),
+model_b AS (
+    SELECT * FROM {{ ref('model_b') }}
+)
+SELECT
+    a.id,
+    a.name,
+    b.created_at
+FROM
+    model_a AS a
+JOIN
+    model_b AS b
+    ON a.id = b.id

dev/dags/dbt/multiple_parents_test/models/model_a.sql

@@ -0,0 +1,4 @@
+-- Create a simple table
+SELECT 1 AS id, 'Alice' AS name
+UNION ALL
+SELECT 2 AS id, 'Bob' AS name

dev/dags/dbt/multiple_parents_test/models/model_b.sql

@@ -0,0 +1,4 @@
+-- Create another simple table
+SELECT 1 AS id, '2024-12-25'::date AS created_at
+UNION ALL
+SELECT 2 AS id, '2024-12-26'::date AS created_at

dev/dags/dbt/multiple_parents_test/models/schema.yml

@@ -0,0 +1,32 @@
+version: 2
+
+models:
+  - name: model_a
+    description: "A simple model with user data"
+    tests:
+      - unique:
+          column_name: id
+
+  - name: model_b
+    description: "A simple model with date data"
+    tests:
+      - unique:
+          column_name: id
+
+  - name: combined_model
+    description: "Combines data from model_a and model_b"
+    columns:
+      - name: id
+        tests:
+          - not_null
+
+      - name: name
+        tests:
+          - not_null
+
+      - name: created_at
+        tests:
+          - not_null
+
+    tests:
+      - custom_test_combined_model: {}

dev/dags/dbt/multiple_parents_test/profiles.yml

@@ -0,0 +1,12 @@
+default:
+  target: dev
+  outputs:
+    dev:
+      type: postgres
+      host: "{{ env_var('POSTGRES_HOST') }}"
+      user: "{{ env_var('POSTGRES_USER') }}"
+      password: "{{ env_var('POSTGRES_PASSWORD') }}"
+      port: "{{ env_var('POSTGRES_PORT') | int }}"
+      dbname: "{{ env_var('POSTGRES_DB') }}"
+      schema: "{{ env_var('POSTGRES_SCHEMA') }}"
+      threads: 4

dev/dags/example_tests_multiple_parents.py

@@ -0,0 +1,34 @@
+"""
+An example DAG that uses Cosmos to render a dbt project into an Airflow DAG.
+"""
+
+import os
+from datetime import datetime
+from pathlib import Path
+
+from cosmos import DbtDag, ProfileConfig, ProjectConfig
+from cosmos.profiles import PostgresUserPasswordProfileMapping
+
+DEFAULT_DBT_ROOT_PATH = Path(__file__).parent / "dbt"
+DBT_ROOT_PATH = Path(os.getenv("DBT_ROOT_PATH", DEFAULT_DBT_ROOT_PATH))
+
+profile_config = ProfileConfig(
+    profile_name="default",
+    target_name="dev",
+    profile_mapping=PostgresUserPasswordProfileMapping(
+        conn_id="example_conn",
+        profile_args={"schema": "public"},
+        disable_event_tracking=True,
+    ),
+)
+
+example_multiple_parents_test = DbtDag(
+    # dbt/cosmos-specific parameters
+    project_config=ProjectConfig(
+        DBT_ROOT_PATH / "multiple_parents_test",
+    ),
+    profile_config=profile_config,
+    # normal dag parameters
+    start_date=datetime(2023, 1, 1),
+    dag_id="example_multiple_parents_test",
+)

tests/dbt/parser/test_project.py

@@ -74,7 +74,7 @@ def test_LegacyDbtProject__handle_config_file():
 
     dbt_project._handle_config_file(SAMPLE_YML_PATH)
 
-    assert len(dbt_project.tests) == 12
+    assert len(dbt_project.tests) == 10
     assert "not_null_customer_id_customers" in dbt_project.tests
     sample_test = dbt_project.tests["not_null_customer_id_customers"]
     assert sample_test.type == DbtModelType.DBT_TEST

tests/dbt/test_graph.py

@@ -1609,9 +1609,9 @@ def test_save_dbt_ls_cache(mock_variable_set, mock_datetime, tmp_dbt_project_dir
     hash_dir, hash_args = version.split(",")
     assert hash_args == "d41d8cd98f00b204e9800998ecf8427e"
     if sys.platform == "darwin":
-        assert hash_dir == "2b0b0c3d243f9bfdda0f60b56ab65836"
+        assert hash_dir == "fa5edac64de49909d4b8cbc4dc8abd4f"
     else:
-        assert hash_dir == "cd0535d9a4acb972d74e49eaab85fb6f"
+        assert hash_dir == "9c9f712b6f6f1ace880dfc7f5f4ff051"
 
 
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