From c089d6fb64fa68a2766a8f6f2b2f0021b336e15b Mon Sep 17 00:00:00 2001
From: Michelle Ark <michelle.ark@dbtlabs.com>
Date: Mon, 25 Nov 2024 12:23:31 -0500
Subject: [PATCH] add unit tests for artifact mixin

---
 tests/unit/artifacts/test_artifact_mixin.py | 62 +++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 tests/unit/artifacts/test_artifact_mixin.py

diff --git a/tests/unit/artifacts/test_artifact_mixin.py b/tests/unit/artifacts/test_artifact_mixin.py
new file mode 100644
index 00000000000..31961d96cde
--- /dev/null
+++ b/tests/unit/artifacts/test_artifact_mixin.py
@@ -0,0 +1,62 @@
+
+from dataclasses import dataclass
+import pytest
+
+
+from dbt.artifacts.schemas.base import (
+    ArtifactMixin,
+    BaseArtifactMetadata,
+    schema_version,
+)
+
+@dataclass
+@schema_version("manifest", 12)
+class Artifact(ArtifactMixin):
+    a: int
+
+
+@dataclass
+@schema_version("manifest", 12)
+class ArtifactMinorSchemaChange(ArtifactMixin):
+    a: int
+    b: int = 2
+
+
+class TestMinorSchemaChange:
+    @pytest.fixture
+    def artifact(self):
+        return Artifact(a = 1, metadata=BaseArtifactMetadata(dbt_schema_version="1.9.0"))
+
+    @pytest.fixture
+    def artifact_minor_schema_change(self):
+        return ArtifactMinorSchemaChange(a=1, metadata=BaseArtifactMetadata(dbt_schema_version="1.9.0"))
+
+    def test_serializing_new_default_field_is_backward_compatabile(
+        self, artifact_minor_schema_change
+    ):
+        # old code (using old class) can create an instance of itself given new data (new class)
+        artifact = Artifact.from_dict(artifact_minor_schema_change.to_dict())
+        
+        assert artifact.a == 1
+        # Additional fields are ignored
+        assert not hasattr(artifact, "b")
+
+    def test_serializing_new_default_field_is_forward_compatible(self, artifact):
+        # new code (using new class) can create an instance of itself given old data (old class)
+        artifact = ArtifactMinorSchemaChange.from_dict(artifact.to_dict())
+
+        assert artifact.a == 1
+        assert artifact.b == 2
+
+    def test_serializing_removed_default_field_is_backward_compatabile(self, artifact):
+        # old code (using old class with default field) can create an instance of itself given new data (class w/o default field)
+        old_artifact = ArtifactMinorSchemaChange.from_dict(artifact.to_dict())
+        
+        # set to the default value when not provided in data
+        assert old_artifact.b == 2
+
+    def test_serializing_removed_default_field_is_forward_compatible(
+        self, artifact_minor_schema_change
+    ):
+        # new code (using class without default field) can create an instance of itself given old data (class with old field)
+        Artifact.from_dict(artifact_minor_schema_change.to_dict())
\ No newline at end of file