diff --git a/app/other/apis/tools/db_columns_test.go b/app/other/apis/tools/db_columns_test.go
index 34898242..e4681cfe 100644
--- a/app/other/apis/tools/db_columns_test.go
+++ b/app/other/apis/tools/db_columns_test.go
@@ -24,9 +24,15 @@ type bodyOf struct {
 	Msg  string `json:"msg"`
 }
 
-// newColumnListEngine wires the handler the way the router does, including the
+// newEngine wires one generator handler the way the router does, including the
 // middleware that turns pkg.Assert's panic into a response.
-func newColumnListEngine(t *testing.T) *gin.Engine {
+//
+// The generator's queries target MySQL's information_schema and cannot run on
+// the sqlite connection behind them; the driver setting only has to select that
+// branch, since no statement here is expected to succeed. That makes this
+// serviceable for any handler in this package whose behaviour is decided before
+// the query goes out -- which is what these tests are about.
+func newEngine(t *testing.T, method, path string, h gin.HandlerFunc) *gin.Engine {
 	t.Helper()
 	gin.SetMode(gin.TestMode)
 
@@ -35,26 +41,33 @@ func newColumnListEngine(t *testing.T) *gin.Engine {
 		t.Fatalf("open sqlite: %v", err)
 	}
 
-	// The query targets MySQL's information_schema; the driver setting only has
-	// to select that branch, the statement itself is never expected to succeed.
 	previous := config.DatabaseConfig.Driver
 	config.DatabaseConfig.Driver = "mysql"
 	t.Cleanup(func() { config.DatabaseConfig.Driver = previous })
 
 	r := gin.New()
 	r.Use(middleware.CustomError)
-	r.GET("/db/columns/page", func(c *gin.Context) {
+	r.Handle(method, path, func(c *gin.Context) {
 		c.Set("db", db)
 		c.Set(pkg.LoggerKey, logger.NewHelper(logger.DefaultLogger))
-		Gen{}.GetDBColumnList(c)
+		h(c)
 	})
 	return r
 }
 
-func columnListMsg(t *testing.T, r *gin.Engine, query string) bodyOf {
+func newColumnListEngine(t *testing.T) *gin.Engine {
+	t.Helper()
+	return newEngine(t, http.MethodGet, "/db/columns/page", Gen{}.GetDBColumnList)
+}
+
+// serveJSON runs one request through the engine and decodes the envelope every
+// handler here answers with. A body that will not decode fails the test rather
+// than being reported as a mismatched message, which reads as the handler
+// having answered something unexpected instead of not having answered at all.
+func serveJSON(t *testing.T, r *gin.Engine, req *http.Request) bodyOf {
 	t.Helper()
 	w := httptest.NewRecorder()
-	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/db/columns/page"+query, nil))
+	r.ServeHTTP(w, req)
 
 	var body bodyOf
 	if err := json.Unmarshal(w.Body.Bytes(), &body); err != nil {
@@ -63,6 +76,11 @@ func columnListMsg(t *testing.T, r *gin.Engine, query string) bodyOf {
 	return body
 }
 
+func columnListMsg(t *testing.T, r *gin.Engine, query string) bodyOf {
+	t.Helper()
+	return serveJSON(t, r, httptest.NewRequest(http.MethodGet, "/db/columns/page"+query, nil))
+}
+
 func TestGetDBColumnList_AcceptsATableName(t *testing.T) {
 	body := columnListMsg(t, newColumnListEngine(t), "?tableName=sys_user")
 	if body.Msg == emptyTableNameMsg {