diff --git a/tests/Makefile b/tests/Makefile
index 48fc38b..828522c 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -1,15 +1,21 @@
 .PHONY: all clean
 
-all: basic unit_test
+CFLAGS+=-Wall -g -I ../include -I../asn1-compiled
+LDFLAGS+=-L../src -L../asn1-compiled
+
+all: basic unit_test wrap_tcap_decode
 
 basic: basic.c ../src/libtcap.so.0
-	gcc -Wall -g -I ../include -I../asn1-compiled basic.c -o basic -L../src -ltcap
+	gcc -o $@ $(CFLAGS) basic.c $(LDFLAGS) ../src/tcap.o ../asn1-compiled/libtcap-asn.a
 
-../src/libtcap.so.0:
-	cd .. && make all
+../src/tcap.o: ../src/tcap.c
+	gcc -o $@ $(CFLAGS) -c ../src/tcap.c
 
 unit_test: unit_test.c
-	gcc -Wall -g -I ../include -I../asn1-compiled unit_test.c -o unit_test -L../src -lcmocka -ltcap
+	gcc -o $@ $(CFLAGS) unit_test.c $(LDFLAGS) -lcmocka ../src/tcap.o ../asn1-compiled/libtcap-asn.a
+
+wrap_tcap_decode: wrap_tcap_decode.c
+	gcc -o $@ $(CFLAGS) $(LDFLAGS) -lcmocka -Wl,-wrap,cap_decode ../src/tcap.o ../asn1-compiled/libtcap-asn.a wrap_tcap_decode.c
 
 clean:
-	rm -f basic unit_test
+	rm -f basic unit_test wrap_tcap_decode
diff --git a/tests/wrap_tcap_decode.c b/tests/wrap_tcap_decode.c
new file mode 100644
index 0000000..5f7a97b
--- /dev/null
+++ b/tests/wrap_tcap_decode.c
@@ -0,0 +1,44 @@
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+#include "libtcap.h"
+#include "TCMessage.h"
+
+TCMessage_t *__wrap_tcap_decode(const char *buf, size_t len) {
+	TCMessage_t *ret = NULL;
+
+	printf("Hi\n");
+	check_expected(buf);
+	check_expected(len);
+
+	// allways fail
+	return ret;
+}
+
+const char tcap[] = "\x64\x81\x86\x49\x03\x0a\x7e\x71\x6b\x2a\x28\x28\x06\x07\x00\x11\x86\x05\x01\x01\x01\xa0\x1d\x61\x1b\xa1\x0d\x06\x0b\x2a\x81\x76\x82\x15\x01\x01\x01\x01\x00\x01\xa2\x03\x02\x01\x00\xa3\x05\xa1\x03\x02\x01\x00\x6c\x53\xa1\x10\x02\x01\x58\x02\x01\x22\xbf\x33\x07\x83\x05\x31\x30\x30\x32\x34\xa1\x3f\x02\x01\x59\x02\x01\x14\x30\x37\xa0\x0e\x04\x0c\x83\x90\x89\x10\x10\x80\x22\x08\x00\x55\x50\x05\x83\x01\x09\x9a\x22\x30\x20\xa0\x1e\x80\x01\x00\x81\x01\x00\x82\x01\x01\x83\x01\x01\x84\x01\x00\x85\x01\x00\x86\x01\x01\x87\x01\x01\x88\x01\x00\x89\x01\x00";
+const int tcap_len = sizeof(tcap) - 1;
+struct output_buffer out;
+char buf[256];
+
+static void test_localValue(void **state) {
+    int i;
+	OUTPUT_BUFFER_INIT(&out, buf);
+
+	//expect_memory(__wrap_tcap_decode, buf, tcap, tcap_len);
+	//expect_value(__wrap_tcap_decode, len, tcap_len);
+
+	i = tcap_extract(tcap, tcap_len, "end.components.1.invoke.opCode.localValue", &out);
+    assert_int_equal(i, 0);
+    assert_int_equal(out.used, 2);
+    out.buf[2] = '\0';
+    assert_string_equal(out.buf, "20");
+}
+
+int main(void) {
+    const UnitTest tests[] = {
+        unit_test(test_localValue),
+    };
+    return run_tests(tests);
+}
\ No newline at end of file