Add roundtrip export to database checks

Author: tgnottingham

.github/workflows/ci.yml

@@ -183,3 +183,21 @@ jobs:
 
       - name: Export empty SQLite DB to Postgres
         run: ./target/debug/sqlite-to-postgres "$(mktemp)" 'postgresql://postgres:postgres@localhost:5432/postgres'
+
+      - name: Roundtrip export
+        run: |
+            sudo apt-get update
+            sudo apt-get install -y wget python3-snappy sqlite3
+
+            wget -q 'http://perf-data.rust-lang.org/export.db.sz'
+            python3 -m snappy -d export.db.sz > before.db
+
+            ./target/debug/sqlite-to-postgres before.db 'postgresql://postgres:postgres@localhost:5432/postgres'
+            sqlite3 before.db .dump > before.dump
+
+            rm before.db
+
+            ./target/debug/postgres-to-sqlite 'postgresql://postgres:postgres@localhost:5432/postgres' after.db
+            sqlite3 after.db .dump > after.dump
+
+            diff -w before.dump after.dump