add a go fmt test.

.github/workflows/basictests.yml

@@ -17,6 +17,14 @@ jobs:
         go-version: ${{ matrix.go-version }}
     - name: Checkout code
       uses: actions/checkout@v4
+    - name: Check formatting
+      run: |
+        # Check formatting of all Go files in the project
+        if [ "$(gofmt -s -l $(find . -name "*.go" -type f) | wc -l)" -gt 0 ]; then
+          echo "The following files are not formatted with go fmt:"
+          gofmt -s -l $(find . -name "*.go" -type f)
+          exit 1
+        fi
     - name: Test
       run: |
         go build -tags appengine

smat.go

@@ -78,8 +78,6 @@ type actionRecord struct {
 	PairSnapshots []string // base64-encoded MarshalBinary of each pair's Bitmap
 }
 
-var ()
-
 type smatPair struct {
 	bm *Bitmap
 	bs *bitset.BitSet