Changes:完整窗口均值计算以及对应测试代码完成

average.py

@@ -26,12 +26,16 @@ class average(algorithm):
         self.present_number_ = len(self.window_1_)
         if self.present_number_ < self.average_number_:
             self.window_1_.append(value)
-            return
-        else:
             self.sum = 0
             for i in self.window_1_:
                 self.sum = self.sum + i
             self.average = self.sum / len(self.window_1_)
+            return self.average
+        else:
+            self.sum = 0
             del self.window_1_[0]
             self.window_1_.append(value)
+            for i in self.window_1_:
+                self.sum = self.sum + i
+            self.average = self.sum / len(self.window_1_)
             return self.average