[Issue #3973] Guard against null mime type / description / file size (#…

…3991)

## Summary
Fixes #3973

### Time to review: 5 mins

## Changes proposed
Quick follow on PR to check more fields.

## Context for reviewers
Test failed for other missing fields we want to guard against.

api/src/data_migration/transformation/subtask/transform_opportunity_attachment.py

@@ -200,6 +200,14 @@ def transform_opportunity_attachment(
     if source_attachment.mime_type is None:
         raise ValueError("Opportunity attachment does not have a mime type, cannot process.")
 
+    # We should always have a file description. Raise an error if we don't
+    if source_attachment.file_desc is None:
+        raise ValueError("Opportunity attachment does not have a file description, cannot process.")
+
+    # We should always have a file size. Raise an error if we don't
+    if source_attachment.file_lob_size is None:
+        raise ValueError("Opportunity attachment does not have a file size, cannot process.")
+
     file_location = attachment_util.get_s3_attachment_path(
         file_name, source_attachment.syn_att_id, opportunity, s3_config
     )

api/tests/src/data_migration/transformation/subtask/test_transform_opportunity_attachment.py

@@ -271,3 +271,44 @@ def test_transform_opportunity_attachment_null_mime_type(
             )
 
         assert insert.transformed_at is None
+
+    def test_transform_opportunity_attachment_null_file_description(
+        self, db_session, transform_opportunity_attachment, s3_config
+    ):
+        opportunity = f.OpportunityFactory.create(opportunity_attachments=[])
+        insert = setup_opportunity_attachment(
+            create_existing=False,
+            opportunity=opportunity,
+            config=s3_config,
+            source_values={"file_desc": None},
+        )
+
+        with pytest.raises(
+            ValueError,
+            match="Opportunity attachment does not have a file description, cannot process",
+        ):
+            transform_opportunity_attachment.process_opportunity_attachment(
+                insert, None, opportunity
+            )
+
+        assert insert.transformed_at is None
+
+    def test_transform_opportunity_attachment_null_file_size(
+        self, db_session, transform_opportunity_attachment, s3_config
+    ):
+        opportunity = f.OpportunityFactory.create(opportunity_attachments=[])
+        insert = setup_opportunity_attachment(
+            create_existing=False,
+            opportunity=opportunity,
+            config=s3_config,
+            source_values={"file_lob_size": None},
+        )
+
+        with pytest.raises(
+            ValueError, match="Opportunity attachment does not have a file size, cannot process"
+        ):
+            transform_opportunity_attachment.process_opportunity_attachment(
+                insert, None, opportunity
+            )
+
+        assert insert.transformed_at is None