Check formatting in CI via rustfmt

.github/workflows/test.yml

@@ -23,8 +23,20 @@ jobs:
       - name: Run cargo clippy
         run: cargo clippy --all-targets
 
+  fmt:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust nightly with rustfmt
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: rustfmt
+
+      - name: Run rustfmt --check
+        run: cargo fmt -- --check
+
   test:
-    needs: clippy
+    needs: [clippy, fmt]
     runs-on: ${{ matrix.os }}
     strategy:
       matrix: