Add a migration to convert request statuses

alembic/versions/77b065750596_new_request_statuses.py

@@ -0,0 +1,49 @@
+"""new request statuses
+
+Revision ID: 77b065750596
+Revises: 1f57f784ed5b
+Create Date: 2018-08-07 16:42:11.502361
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.orm.session import sessionmaker
+
+from atst.models.request_status_event import RequestStatus
+
+
+# revision identifiers, used by Alembic.
+revision = '77b065750596'
+down_revision = '1f57f784ed5b'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    """
+    Update all existing request statuses so that the state of the
+    table reflects the statuses listed in RequestStatus.
+
+    This involves fixing the casing on existing statuses, and
+    deleting statuses that have no match.
+    """
+
+    db = op.get_bind()
+
+    status_events = db.execute("SELECT * FROM request_status_events").fetchall()
+    for status_event in status_events:
+        try:
+            status = RequestStatus[status_event["new_status"].upper()]
+            query = sa.text("""
+                UPDATE request_status_events
+                SET new_status = :status
+                WHERE id = :id"""
+            )
+            db.execute(query, id=status_event["id"], status=status.name)
+        except ValueError:
+            query = sa.text("DELETE FROM request_status_events WHERE id = :id")
+            db.execute(query, id=status_event["id"])
+
+
+def downgrade():
+    pass