diff --git a/skeletons/tests/check-length.c b/skeletons/tests/check-length.c
new file mode 100644
index 0000000..d0edde3
--- /dev/null
+++ b/skeletons/tests/check-length.c
@@ -0,0 +1,93 @@
+#include <ber_decoder.c>
+#include <ber_tlv_length.c>
+#include <ber_tlv_tag.c>
+#include <der_encoder.c>
+#include <constraints.c>
+#undef	ADVANCE
+#undef	RETURN
+#undef	LEFT
+#include <OCTET_STRING.c>
+
+
+uint8_t *buf;
+size_t buf_size;
+size_t buf_off;
+
+static int
+write_to_buf(const void *buffer, size_t size, void *key) {
+	(void)key;
+
+	if(buf_off + size > buf_size) {
+		size_t n = buf_size?:16;
+		while(n < buf_off + size) n <<= 2;
+		buf = realloc(buf, n);
+		assert(buf);
+		buf_size = n;
+	}
+
+	memcpy(buf + buf_off, buffer, size);
+
+	buf_off += size;
+	return 0;
+}
+
+
+static void
+check(int size) {
+	OCTET_STRING_t *os;
+	OCTET_STRING_t *nos = 0;
+	der_enc_rval_t erval;
+	ber_dec_rval_t rval;
+	int i;
+
+	os = OCTET_STRING_new_fromBuf(0, size);
+	assert(os);
+	assert(os->size == 0);
+
+	os->buf = malloc(size);
+	assert(os->buf);
+	os->size = size;
+
+	for(i = 0; i < size; i++) {
+		os->buf[i] = i;
+	}
+
+	buf_off = 0;
+	erval = der_encode(&asn1_DEF_OCTET_STRING,
+		os, write_to_buf, 0);
+	assert(erval.encoded == buf_off);
+	assert(buf_off > size);
+
+	rval = ber_decode(&asn1_DEF_OCTET_STRING, &nos, buf, buf_off);
+	assert(rval.code == RC_OK);
+	assert(rval.consumed == buf_off);
+
+	assert(os->size == nos->size);
+
+	for(i = 0; i < size; i++) {
+		assert(os->buf[i] == nos->buf[i]);
+	}
+
+	if(0) {
+	printf("new(%d):", size);
+	for(i = 0; i < (buf_off<10?buf_off:10); i++)
+		printf(" %02x", buf[i]);
+	printf("\n");
+	}
+
+
+	asn1_DEF_OCTET_STRING.free_struct(&asn1_DEF_OCTET_STRING, os, 0);
+	asn1_DEF_OCTET_STRING.free_struct(&asn1_DEF_OCTET_STRING, nos, 0);
+}
+
+int
+main() {
+	int i;
+
+	for(i = 0; i < 66000; i++) {
+		if(i == 4500) i = 64000;
+		check(i);
+	}
+
+	return 0;
+}