chore(cubesql): Clean up unreferenced insta snapshots (#9130)

* chore(cubesql): Clean up unreferenced insta snapshots

* ci(cubesql): Check unreferenced insta snapshots in CI

* try to combine llvm-cov and insta test run

Author: mcheshkov

.github/workflows/rust-cubesql.yml

@@ -85,6 +85,11 @@ jobs:
         with:
           crate: cargo-llvm-cov
           version: "0.6.10"
+      - name: Install [email protected]
+        uses: baptiste0928/cargo-install@v3
+        with:
+          crate: cargo-insta
+          version: "1.42.0"
       - name: Unit tests (Rewrite Engine)
         env:
           CUBESQL_TESTING_CUBE_TOKEN: ${{ secrets.CUBESQL_TESTING_CUBE_TOKEN }}
@@ -94,7 +99,11 @@ jobs:
           CUBESQL_REWRITE_TIMEOUT: 60
         run: |
           cd rust/cubesql
-          cargo llvm-cov --all-features --workspace --lcov --output-path lcov.info
+          # See https://github.com/taiki-e/cargo-llvm-cov/blob/main/README.md#get-coverage-of-external-tests
+          # shellcheck source=/dev/null
+          source <(cargo llvm-cov show-env --export-prefix)
+          cargo insta test --all-features --workspace --unreferenced reject
+          cargo llvm-cov report --lcov --output-path lcov.info
       - name: Upload code coverage
         uses: codecov/codecov-action@v5
         with: