diff --git a/asn1c/tests/check-70.-fnative-types.c b/asn1c/tests/check-70.-fnative-types.c
new file mode 100644
index 0000000..8538f5e
--- /dev/null
+++ b/asn1c/tests/check-70.-fnative-types.c
@@ -0,0 +1,296 @@
+/*
+ * Mode of operation:
+ * Each of the *.in files is XER-decoded, then converted into DER,
+ * then decoded from DER and encoded into XER again. The resulting
+ * stream is compared with the corresponding .out file.
+ */
+#undef	NDEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>	/* for chdir(2) */
+#include <string.h>
+#include <dirent.h>
+#include <ctype.h>	/* for isspace(3) */
+#include <assert.h>
+#include <errno.h>
+
+#include <PDU.h>
+
+enum expectation {
+	EXP_OK,		/* Encoding/decoding must succeed */
+	EXP_BROKEN,	/* Decoding must fail */
+	EXP_DIFFERENT,	/* Reconstruction will yield different encoding */
+};
+
+static unsigned char buf[4096];
+static int buf_offset;
+
+static int
+_buf_writer(const void *buffer, size_t size, void *app_key) {
+	unsigned char *b, *bend;
+	(void)app_key;
+	assert(buf_offset + size < sizeof(buf));
+	memcpy(buf + buf_offset, buffer, size);
+	b = buf + buf_offset;
+	bend = b + size;
+	fprintf(stderr, "=> [");
+	for(; b < bend; b++)
+		fprintf(stderr, "%c", *b);
+	fprintf(stderr, "]:%ld\n", (long)size);
+	buf_offset += size;
+	return 0;
+}
+
+enum der_or_xer {
+	AS_DER,
+	AS_XER,
+};
+
+static void
+save_object_as(PDU_t *st, enum der_or_xer how) {
+	asn_enc_rval_t rval; /* Return value */
+
+	buf_offset = 0;
+
+	/*
+	 * Save object using specified method.
+	 */
+	switch(how) {
+	case AS_DER:
+		rval = der_encode(&asn_DEF_PDU, st,
+			_buf_writer, 0);
+		break;
+	case AS_XER:
+		rval = xer_encode(&asn_DEF_PDU, st, XER_F_BASIC,
+			_buf_writer, 0);
+		break;
+	}
+	if (rval.encoded == -1) {
+		fprintf(stderr,
+			"Cannot encode %s: %s\n",
+			rval.failed_type->name, strerror(errno));
+		assert(rval.encoded != -1);
+		return;
+	}
+
+	fprintf(stderr, "SAVED OBJECT IN SIZE %d\n", buf_offset);
+}
+
+static PDU_t *
+load_object_from(enum expectation expectation, char *fbuf, int size, enum der_or_xer how) {
+	asn_dec_rval_t rval;
+	asn_dec_rval_t (*zer_decode)(struct asn_codec_ctx_s *,
+		asn_TYPE_descriptor_t *, void **, const void *, size_t);
+	PDU_t *st = 0;
+	int csize = 1;
+
+	if(how == AS_DER)
+		zer_decode = ber_decode;
+	else
+		zer_decode = xer_decode;
+
+	if(getenv("INITIAL_CHUNK_SIZE"))
+		csize = atoi(getenv("INITIAL_CHUNK_SIZE"));
+
+	/* Perform multiple iterations with multiple chunks sizes */
+	for(; csize < 20; csize += 1) {
+		int fbuf_offset = 0;
+		int fbuf_left = size;
+		int fbuf_chunk = csize;
+
+		fprintf(stderr, "LOADING OBJECT OF SIZE %d, chunks %d\n",
+			size, csize);
+
+		if(st) asn_DEF_PDU.free_struct(&asn_DEF_PDU, st, 0);
+		st = 0;
+
+		do {
+			fprintf(stderr, "Decoding bytes %d..%d (left %d)\n",
+				fbuf_offset,
+					fbuf_chunk < fbuf_left
+						? fbuf_chunk : fbuf_left,
+					fbuf_left);
+			if(st) {
+				fprintf(stderr, "=== currently ===\n");
+				asn_fprint(stderr, &asn_DEF_PDU, st);
+				fprintf(stderr, "=== end ===\n");
+			}
+			rval = zer_decode(0, &asn_DEF_PDU, (void **)&st,
+				fbuf + fbuf_offset,
+					fbuf_chunk < fbuf_left 
+					? fbuf_chunk : fbuf_left);
+			fbuf_offset += rval.consumed;
+			fbuf_left -= rval.consumed;
+			if(rval.code == RC_WMORE)
+				fbuf_chunk += 1;	/* Give little more */
+			else
+				fbuf_chunk = csize;	/* Back off */
+		} while(fbuf_left && rval.code == RC_WMORE);
+
+		if(expectation != EXP_BROKEN) {
+			assert(rval.code == RC_OK);
+			if(how == AS_DER) {
+				assert(fbuf_offset == size);
+			} else {
+				assert(fbuf_offset - size < 2
+				|| (fbuf_offset + 1 /* "\n" */  == size
+					&& fbuf[size - 1] == '\n')
+				|| (fbuf_offset + 2 /* "\r\n" */  == size
+					&& fbuf[size - 2] == '\r'
+					&& fbuf[size - 1] == '\n')
+				);
+			}
+		} else {
+			assert(rval.code != RC_OK);
+			fprintf(stderr, "Failed, but this was expected\n");
+			asn_DEF_PDU.free_struct(&asn_DEF_PDU, st, 0);
+			st = 0;	/* ignore leak for now */
+		}
+	}
+
+	if(st) asn_fprint(stderr, &asn_DEF_PDU, st);
+	return st;
+}
+
+static int
+xer_encoding_equal(char *obuf, size_t osize, char *nbuf, size_t nsize) {
+	char *oend = obuf + osize;
+	char *nend = nbuf + nsize;
+
+	if((osize && !nsize) || (!osize && nsize))
+		return 0;	/* not equal apriori */
+
+	while(1) {
+		while(obuf < oend && isspace(*obuf)) obuf++;
+		while(nbuf < nend && isspace(*nbuf)) nbuf++;
+
+		if(obuf == oend || nbuf == nend) {
+			if(obuf == oend && nbuf == nend)
+				break;
+			fprintf(stderr, "%s data in reconstructed encoding\n",
+				(obuf == oend) ? "More" : "Less");
+			return 0;
+		}
+
+		if(*obuf != *nbuf) {
+			printf("%c%c != %c%c\n",
+				obuf[0], obuf[1],
+				nbuf[0], nbuf[1]);
+			return 0;
+		}
+		obuf++, nbuf++;
+	}
+
+	return 1;
+}
+
+static void
+process_XER_data(enum expectation expectation, char *fbuf, int size) {
+	PDU_t *st;
+
+	st = load_object_from(expectation, fbuf, size, AS_XER);
+	if(!st) return;
+
+	/* Save and re-load as DER */
+	save_object_as(st, AS_DER);
+	st = load_object_from(expectation, buf, buf_offset, AS_DER);
+	assert(st);
+
+	save_object_as(st, AS_XER);
+	fprintf(stderr, "=== original ===\n");
+	fwrite(fbuf, 1, size, stderr);
+	fprintf(stderr, "=== re-encoded ===\n");
+	fwrite(buf, 1, buf_offset, stderr);
+	fprintf(stderr, "=== end ===\n");
+
+	switch(expectation) {
+	case EXP_DIFFERENT:
+		assert(!xer_encoding_equal(fbuf, size, buf, buf_offset));
+		break;
+	case EXP_BROKEN:
+		assert(!xer_encoding_equal(fbuf, size, buf, buf_offset));
+		break;
+	case EXP_OK:
+		assert(xer_encoding_equal(fbuf, size, buf, buf_offset));
+		break;
+	}
+
+	asn_DEF_PDU.free_struct(&asn_DEF_PDU, st, 0);
+}
+
+/*
+ * Decode the .der files and try to regenerate them.
+ */
+static int
+process(const char *fname) {
+	char fbuf[4096];
+	char *ext = strrchr(fname, '.');
+	enum expectation expectation;
+	int ret;
+	int rd;
+	FILE *fp;
+
+	if(ext == 0 || strcmp(ext, ".in"))
+		return 0;
+
+	switch(ext[-1]) {
+	case 'B':	/* The file is intentionally broken */
+		expectation = EXP_BROKEN; break;
+	case 'X':
+	case 'D':	/* Reconstructing should yield different data */
+		expectation = EXP_DIFFERENT; break;
+	case 'E':
+	default:
+		expectation = EXP_OK; break;
+	}
+
+	fprintf(stderr, "\nProcessing file [../%s]\n", fname);
+
+	ret = chdir("../data-70");
+	assert(ret == 0);
+	fp = fopen(fname, "r");
+	ret = chdir("../test-check-70.-fnative-types");
+	assert(ret == 0);
+	assert(fp);
+
+	rd = fread(fbuf, 1, sizeof(fbuf), fp);
+	fclose(fp);
+
+	assert(rd < sizeof(fbuf));	/* expect small files */
+
+	process_XER_data(expectation, fbuf, rd);
+
+	return 1;
+}
+
+int
+main() {
+	DIR *dir;
+	struct dirent *dent;
+	int processed_files = 0;
+	char *str;
+
+	/* Process a specific test file */
+	str = getenv("DATA_70_FILE");
+	if(str && strncmp(str, "data-70-", 8) == 0)
+		process(str);
+
+	dir = opendir("../data-70");
+	assert(dir);
+
+	/*
+	 * Process each file in that directory.
+	 */
+	while((dent = readdir(dir))) {
+		if(strncmp(dent->d_name, "data-70-", 8) == 0)
+			if(process(dent->d_name))
+				processed_files++;
+	}
+
+	assert(processed_files);
+	closedir(dir);
+
+	return 0;
+}
+