test: UTF-8 round-trip regression for dbt seed

tests/functional/adapter/simple_seed/test_utf8_seed.py

@@ -0,0 +1,31 @@
+import pytest
+from dbt.tests import util
+
+from tests.functional.adapter.fixtures import MaterializationV2Mixin
+
+UTF8_DATA = {
+    "arabic": "مرحبا بالعالم",
+    "greek": "Γειά σου Κόσμε",
+    "chinese": "你好世界",
+    "emoji": "Hello 🌍 World ✨",
+    "mixed": "café naïve résumé — ",
+}
+SEED_CSV = "label,value\n" + "\n".join(f"{k},{v}" for k, v in UTF8_DATA.items())
+
+
+class TestUtf8SeedRoundTrip:
+    @pytest.fixture(scope="class")
+    def seeds(self):
+        return {"utf8_roundtrip.csv": SEED_CSV}
+
+    def test_utf8_roundtrip(self, project):
+        results = util.run_dbt(["seed"])
+        assert len(results) == 1
+
+        relation = util.relation_from_name(project.adapter, "utf8_roundtrip")
+        rows = project.run_sql(f"select label, value from {relation}", fetch="all")
+        assert dict(rows) == UTF8_DATA
+
+
+class TestUtf8SeedRoundTripV2(TestUtf8SeedRoundTrip, MaterializationV2Mixin):
+    pass