diff --git a/src/mpValidations.py b/src/mpValidations.py
new file mode 100644
index 0000000..a1fcac0
--- /dev/null
+++ b/src/mpValidations.py
@@ -0,0 +1,90 @@
+
+
+from mpTcptraceData import *
+
+
+# A checker runs tests, and a test is made of multiple validations
+
+
+# For a validation, the value to compare to is the target value from the yaml
+# The validation takes place in the validate method, which takes
+# as argument a value from which to extract the value to compare or the value itself
+class Validation:
+	def __init__(self, yml):
+		self.compared=yml["target"]
+	def name(self):
+		return self.__class__.__name__
+
+# checks a value passed is greater or equal (generic)
+class MinValueValidation(Validation):
+	def validate(self, value):
+		return self.compared<=value
+
+# individual flow validation (specific)
+# gets flow_spec = (index, flows) where index is the index of the flow to validate, and flows is the array of flows
+class MinDelayValidation(Validation):
+	def validate(self, flow_spec):
+		(index,flows) = flow_spec
+		val = float(flows[index][5])-float(flows[0][5])
+		return self.compared<=val
+
+
+
+# Base class testing tcptrace results
+# the inheriting class should implement get_tested_value(self, yml)
+# The validate method iterates one the validations mentioned for the test in the yml file.
+class TcptraceTest: 
+	def __init__(self, yml, trace):
+		self.yml = yml["validations"]
+		self.trace = trace
+	# performs a validation found in the yml file.
+	def validate(self):
+		is_ok = True
+		self.logs = ""
+		for val in self.yml:
+			tested_value = self.get_tested_value(val) 
+			klass_name=val["name"].title().replace("_","")+"Validation"
+			tester_klass=globals()[klass_name]
+			tester = tester_klass(val)
+			if tester.validate(tested_value):
+				self.logs=self.logs+ ("" if self.logs=="" else "\n ")+ "  -" +tester.name()+" OK\n"
+				return True
+			else:
+				self.logs=self.logs+ ("" if self.logs=="" else "\n ")+ "  -" +tester.name()+" FAILS\n"
+				is_ok = False
+		return is_ok
+	def name(self):
+		return self.__class__.__name__ 
+
+# get_tested_value returns the number of flows
+class NumberOfFlowsTest(TcptraceTest):
+	def get_tested_value(self, yml):
+		return self.trace.number_of_flows
+
+# get_tested_value returns index of the flow to validate, and the list of flows
+class FlowsTest(TcptraceTest):
+	def get_tested_value(self, yml):
+		return (yml["index"],self.trace.flows) 
+
+
+# Runs tests based on tcptrace
+class TcptraceChecker:
+	def __init__(self, yml, test_id):
+		self.yml = yml["tcptrace"]
+		self.trace = TcptraceData("/tmp/dest/client.pcap")
+		self.test_id = test_id
+	def check(self):
+		is_ok = True
+		self.logs=self.test_id+"\n"
+		for test in self.yml:
+			name=test["test"].title().replace("_","")+"Test"
+			klass = globals()[name]
+			r = klass(test, self.trace)
+			if r.validate():
+				self.logs = self.logs + " *" + r.name() + " SUCCESS\n"
+				self.logs = self.logs +  r.logs
+			else:
+				self.logs = self.logs + " *" + self.test_id + " " + r.name() + " FAIL\n"
+				self.logs = self.logs + r.logs
+
+