fix: Check if replication key is timestamp before using start_date as default

singer_sdk/streams/core.py

@@ -409,7 +409,7 @@ def _write_starting_replication_value(self, context: types.Context | None) -> No
 
             # Use start_date if it is more recent than the replication_key state
             start_date_value: str | None = self.config.get("start_date")
-            if start_date_value:
+            if start_date_value and self.is_timestamp_replication_key:
                 if not value:
                     value = start_date_value
                 else:

tests/samples/conftest.py

@@ -97,7 +97,10 @@ def path_to_sample_data_db(tmp_path: Path) -> Path:
 @pytest.fixture
 def sqlite_sample_db_config(path_to_sample_data_db: Path) -> dict:
     """Get configuration dictionary for target-csv."""
-    return {"path_to_db": str(path_to_sample_data_db)}
+    return {
+        "path_to_db": str(path_to_sample_data_db),
+        "start_date": "2010-01-01T00:00:00Z",
+    }
 
 
 @pytest.fixture