Convert default selectors tests to pytest

.changes/unreleased/Under the Hood-20220912-134000.yaml

@@ -0,0 +1,7 @@
+kind: Under the Hood
+body: Convert default selector tests to pytest
+time: 2022-09-12T13:40:00.625912-05:00
+custom:
+  Author: stu-k
+  Issue: "5728"
+  PR: "5820"

tests/functional/selectors/test_default_selectors.py

@@ -0,0 +1,98 @@
+import pytest
+from dbt.tests.util import run_dbt
+
+models__schema_yml = """
+version: 2
+
+sources:
+  - name: src
+    schema: "{{ target.schema }}"
+    freshness:
+      warn_after: {count: 24, period: hour}
+    loaded_at_field: _loaded_at
+    tables:
+      - name: source_a
+        identifier: model_c
+        columns:
+          - name: fun
+          - name: _loaded_at
+  - name: src
+    schema: "{{ target.schema }}"
+    freshness:
+      warn_after: {count: 24, period: hour}
+    loaded_at_field: _loaded_at
+    tables:
+      - name: source_b
+        identifier: model_c
+        columns:
+          - name: fun
+          - name: _loaded_at
+
+models:
+  - name: model_a
+    columns:
+      - name: fun
+        tags: [marketing]
+  - name: model_b
+    columns:
+      - name: fun
+        tags: [finance]
+"""
+
+models__model_a_sql = """
+SELECT 1 AS fun
+"""
+
+models__model_b_sql = """
+SELECT 1 AS fun
+"""
+
+seeds__model_c_csv = """fun,_loaded_at
+1,2021-04-19 01:00:00"""
+
+
+@pytest.fixture(scope="class")
+def models():
+    return {
+        "schema.yml": models__schema_yml,
+        "model_b.sql": models__model_b_sql,
+        "model_a.sql": models__model_a_sql,
+    }
+
+
+@pytest.fixture(scope="class")
+def seeds():
+    return {"model_c.csv": seeds__model_c_csv}
+
+
+@pytest.fixture(scope="class")
+def selectors():
+    return """
+            selectors:
+            - name: default_selector
+              description: test default selector
+              definition:
+                union:
+                  - method: source
+                    value: "test.src.source_a"
+                  - method: fqn
+                    value: "model_a"
+              default: true
+        """
+
+
+class TestDefaultSelectors:
+    def test_model__list(self, project):
+        result = run_dbt(["ls", "--resource-type", "model"])
+        assert "test.model_a" in result
+
+    def test_model__compile(self, project):
+        result = run_dbt(["compile"])
+        assert len(result) == 1
+        assert result.results[0].node.name == "model_a"
+
+    def test_source__freshness(self, project):
+        run_dbt(["seed", "-s", "test.model_c"])
+        result = run_dbt(["source", "freshness"])
+        assert len(result) == 1
+        assert result.results[0].node.name == "source_a"