修复测试错误

__test__/Line/line.test.ts

@@ -204,7 +204,7 @@ test('直线合并容差', () =>
     let l2 = new Line(new Vector3(10 + 1e-6), new Vector3(15));
     expect(l1.Join(l2)).toBeTruthy();
     l2 = new Line(new Vector3(-10), new Vector3(0 - 1e-5));
-    expect(l1.Join(l2)).toBeTruthy();
+    expect(l1.Join(l2, true, 1e-6)).toBeTruthy();
 });
 
 test('直线合并不平行', () =>

src/Geometry/GeUtils.ts

@@ -136,6 +136,9 @@ export function angleTo(v1: Vector3, v2: Vector3, ref: Vector3 = ZAxis): number
         v2.z = 0;
     }
 
+    if (v1.equals(ZeroVec) || v2.equals(ZeroVec))//修复,这里有可能被更改为0
+        return 0;
+
     //法向量不能转成单位向量在判断，可能会导致原先z===0被转成大于0
     let cv = new Vector3().crossVectors(v1.normalize(), v2.normalize());
     return equaln(cv.z, 0) ? v1.angleTo(v2) : v1.angleTo(v2) * cv.z;