diff --git a/.gitignore b/.gitignore
index 3f3389f41..82c6ff6ef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,3 +24,9 @@ example
 unittest
 
 *.swp
+*.gcov
+
+covtest
+unittest.gcda
+unittest.gcno
+
diff --git a/Makefile b/Makefile
index 51ccf6561..0518690af 100644
--- a/Makefile
+++ b/Makefile
@@ -1,12 +1,22 @@
-all: example
-# unittest
+all: covtest example
 example: example.cpp flask.h http_server.h http_connection.h parser.h http_response.h routing.h common.h
 	g++ -Wall -g -O2 -std=c++11 -o example example.cpp http-parser/http_parser.c -pthread -lboost_system -lboost_thread -I http-parser/
-test: example
+
+test: covtest
+
+runtest: example
 	pkill example || exit 0
 	./example &
 	python test.py || exit 0
 	pkill example
-unittest: unittest.cpp routing.h
-	g++ -g -std=c++11 -o unittest unittest.cpp
+
+unittest: unittest.cpp routing.h
+	g++ -Wall -g -O2 -std=c++11 -o unittest unittest.cpp
+	./unittest
+
+covtest: unittest.cpp routing.h
+	g++ -Wall -g -O2 -std=c++11 --coverage -o covtest unittest.cpp -fkeep-inline-functions -fno-default-inline -fno-inline-small-functions
+	./covtest
+	gcov -r unittest.cpp
+
 
diff --git a/routing.h b/routing.h
index 62f7d8039..539c3aa85 100644
--- a/routing.h
+++ b/routing.h
@@ -9,6 +9,8 @@
 
 #include "common.h"
 #include "http_response.h"
+#include "http_request.h"
+#include "utility.h"
 
 //TEST
 #include <iostream>
@@ -66,6 +68,8 @@ namespace flask
         {
             static_assert(black_magic::CallHelper<Func, black_magic::S<>>::value, 
                 "Handler type is mismatched with URL paramters");
+            static_assert(!std::is_same<void, decltype(f())>::value, 
+                "Handler function cannot have void return type; valid return types: string, int, flask::resposne");
             handler_ = [f = std::move(f)]{
                 return response(f());
             };
@@ -308,7 +312,7 @@ public:
                         { ParamType::PATH, "<path>" },
                     };
 
-                    for(auto it = begin(paramTraits); it != end(paramTraits); ++it)
+                    for(auto it = std::begin(paramTraits); it != std::end(paramTraits); ++it)
                     {
                         if (url.compare(i, it->name.size(), it->name) == 0)
                         {
diff --git a/unittest.cpp b/unittest.cpp
index eaf4466a2..5bdd91185 100644
--- a/unittest.cpp
+++ b/unittest.cpp
@@ -1,10 +1,64 @@
 #include <iostream>
+#include <vector>
+#include "routing.h"
 using namespace std;
+using namespace flask;
+
+struct Test { Test(); virtual void test() = 0; };
+vector<Test*> tests;
+Test::Test() { tests.push_back(this); }
+
+bool failed__ = false;
+void fail() { failed__ = true; }
+
+#define TEST(x) struct test##x:public Test{void test();}x##_; \
+    void test##x::test()
+
+TEST(Rule)
+{
+    Rule r("/http/");
+    r.name("abc");
+    try 
+    {
+        r.validate();
+        fail();
+    }
+    catch(runtime_error& e)
+    {
+    }
+
+    int x = 0;
+
+    r([&x]{x = 1;return "";});
+    r.validate();
+    if (x!=0)
+        fail();
+    r.handle(request(), routing_params());
+    if (x == 0)
+        fail();
+
+}
+
+int testmain()
+{
+    bool failed = false;
+    for(auto t:tests)
+    {
+        failed__ = false;
+        t->test();
+        if (failed__)
+        {
+            cerr << "F";
+            failed = true;
+        }
+        else
+            cerr << ".";
+    }
+    cerr<<endl;
+    return failed ? -1 : 0;
+}
 
 int main()
 {
-    //cout << strtol("+123999999999999999999", NULL, 10) <<endl;
-    //cout <<errno <<endl;
-    cout << strtol("+9223372036854775807", NULL, 10) <<endl;
-    cout <<errno <<endl;
+    return testmain();
 }