ModelTranslator: 质量门抽纯函数 uv_gate_ok + 减面 none 模式（rizom 管线前置）

Tools/ModelTranslator/tests/test_bl_decimate.py

@@ -75,5 +75,22 @@ class TestFillRatio(unittest.TestCase):
         self.assertEqual(bd.fill_ratio([]), 0.0)
 
 
+class TestUvGateOk(unittest.TestCase):
+    def test_clean_passes(self):
+        self.assertTrue(bd.uv_gate_ok(0.0, 0.0))
+
+    def test_boundary_passes(self):
+        self.assertTrue(bd.uv_gate_ok(bd.UV_FLIP_TOL, bd.UV_OVERLAP_TOL))
+
+    def test_flip_exceeds_fails(self):
+        self.assertFalse(bd.uv_gate_ok(0.03, 0.0))
+
+    def test_overlap_exceeds_fails(self):
+        self.assertFalse(bd.uv_gate_ok(0.0, 0.09))
+
+    def test_overlap_none_treated_as_zero(self):
+        self.assertTrue(bd.uv_gate_ok(0.01, None))
+
+
 if __name__ == "__main__":
     unittest.main()