fix test

Author: MindFreeze

test/specs/pan.spec.js

@@ -87,11 +87,11 @@ describe('pan', function () {
       expect(scale.min).toBe(1)
       expect(scale.max).toBe(3)
       chart.pan(-2000)
-      expect(scale.min).toBe(2)
-      expect(scale.max).toBe(4)
+      expect(scale.min).toBe(1)
+      expect(scale.max).toBe(3)
       chart.pan(-2000)
-      expect(scale.min).toBe(2)
-      expect(scale.max).toBe(4)
+      expect(scale.min).toBe(1)
+      expect(scale.max).toBe(3)
       chart.pan(50)
       expect(scale.min).toBeLessThan(2)
       expect(scale.max).toBe(scale.min + 2)