diff --git a/skeletons/tests/check-INTEGER.c b/skeletons/tests/check-INTEGER.c
new file mode 100644
index 0000000..4053075
--- /dev/null
+++ b/skeletons/tests/check-INTEGER.c
@@ -0,0 +1,56 @@
+#include "../INTEGER.c"
+#include "../ber_decoder.c"
+#include "../ber_tlv_length.c"
+#include "../ber_tlv_tag.c"
+#include "../der_encoder.c"
+#include "../constraints.c"
+
+static void
+check(uint8_t *buf, int size, long check_long, int check_ret) {
+	INTEGER_t val;
+	int ret;
+	long rlong = 123;
+
+	assert(buf);
+	assert(size >= 0);
+
+	val.buf = buf;
+	val.size = size;
+
+
+	ret = asn1_INTEGER2long(&val, &rlong);
+	printf("Testing (%ld, %d) vs (%ld, %d)\n",
+		rlong, ret, check_long, check_ret);
+	assert(ret == check_ret);
+	if(ret == -1) return;
+	assert(rlong == check_long);
+}
+
+int
+main(int ac, char **av) {
+	uint8_t buf1[] = { 1 };
+	uint8_t buf2[] = { 0xff };
+	uint8_t buf3[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+	uint8_t buf4[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xf0 };
+	uint8_t buf5[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1 };
+	uint8_t buf6[] = { 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
+	uint8_t buf7[] = { 0xff, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
+	uint8_t buf8[] = { 0x7f, 0x7e, 0x7d, 0x7c };
+	uint8_t buf9[] = { 0, 0x7f, 0x7e, 0x7d, 0x7c };
+	uint8_t buf10[] = { 0, 0, 0, 0, 0, 0, 0x7f, 0x7e, 0x7d, 0x7c };
+
+#define	CHECK(buf, val, ret)	check(buf, sizeof(buf), val, ret)
+
+	CHECK(buf1, 1, 0);
+	CHECK(buf2, -1, 0);
+	CHECK(buf3, -1, 0);
+	CHECK(buf4, -16, 0);
+	CHECK(buf5, 257, 0);
+	CHECK(buf6, 123, -1);
+	CHECK(buf7, 123, -1);
+	CHECK(buf8, 0x7F7E7D7C, 0);
+	CHECK(buf9, 0x7F7E7D7C, 0);
+	CHECK(buf10, 0x7F7E7D7C, 0);
+
+	return 0;
+}