Add more unit tests

backend/internal/api/middleware/access_control_test.go

@@ -0,0 +1,25 @@
+package middleware_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"npm/internal/api/middleware"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAccessControl(t *testing.T) {
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	})
+
+	rr := httptest.NewRecorder()
+	req, err := http.NewRequest("GET", "/", nil)
+	assert.Nil(t, err)
+	accessControl := middleware.AccessControl(handler)
+	accessControl.ServeHTTP(rr, req)
+	assert.Equal(t, http.StatusOK, rr.Code)
+	assert.Equal(t, "*", rr.Header().Get("Access-Control-Allow-Origin"))
+}