Add ttVisitor test

Tests/ttLib/ttVisitor_test.py

@@ -0,0 +1,18 @@
+from fontTools.ttLib import TTFont
+from fontTools.ttLib.ttVisitor import TTVisitor
+import os
+import pytest
+
+
+class TTVisitorTest(object):
+
+    @staticmethod
+    def getpath(testfile):
+        path = os.path.dirname(__file__)
+        return os.path.join(path, "data", testfile)
+
+    def test_ttvisitor(self):
+
+        font = TTFont(self.getpath("TestVGID-Regular.otf"))
+        visitor = TTVisitor()
+        visitor.visit(font, 1, 2, arg=3)