Adding more IGMP test cases
diff --git a/src/test/utils/Stats.py b/src/test/utils/Stats.py
new file mode 100644
index 0000000..3d8e40c
--- /dev/null
+++ b/src/test/utils/Stats.py
@@ -0,0 +1,34 @@
+from math import sqrt
+
+class Stats:
+      def __init__(self):
+            self.count = 0
+            self.start = 0
+            self.delta = 0
+            self.min = 0
+            self.max = 0
+            self.delta_squares = 0
+
+      def update(self, packets = 0, t = 0):
+            self.count += packets
+            t *= 1000000 ##convert to usecs
+            if self.start == 0:
+                  self.start = t
+            self.delta += t
+            self.delta_squares += t*t
+            if self.min == 0 or t < self.min:
+                  self.min = t
+            if self.max == 0 or t > self.max:
+                  self.max = t
+
+      def __repr__(self):
+            if self.count == 0:
+                  self.count = 1
+            mean = self.delta/self.count
+            mean_square = mean*mean
+            delta_square_mean = self.delta_squares/self.count
+            std_mean = sqrt(delta_square_mean - mean_square)
+            r = 'Avg %.3f usecs, Std deviation %.3f usecs, Min %.3f, Max %.3f for %d packets\n' %(
+                  mean, std_mean, self.min, self.max, self.count)
+            return r
+