diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3dc9bd9..9d14350 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -7,7 +7,8 @@
                  conv/conv_test auth/milenage_test lapd/lapd_test	\
                  gsm0808/gsm0808_test gsm0408/gsm0408_test		\
 		 gb/bssgp_fc_test gb/gprs_bssgp_test gb/gprs_ns_test	\
-		 kasumi/kasumi_test logging/logging_test fr/fr_test	\
+		 gprs/gprs_test	kasumi/kasumi_test			\
+		 logging/logging_test fr/fr_test			\
 		 loggingrb/loggingrb_test strrb/strrb_test              \
 		 vty/vty_test comp128/comp128_test utils/utils_test	\
 		 smscb/gsm0341_test stats/stats_test
@@ -46,6 +47,9 @@
 gsm0408_gsm0408_test_SOURCES = gsm0408/gsm0408_test.c
 gsm0408_gsm0408_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
 
+gprs_gprs_test_SOURCES = gprs/gprs_test.c
+gprs_gprs_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
+
 lapd_lapd_test_SOURCES = lapd/lapd_test.c
 lapd_lapd_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
 
@@ -117,8 +121,8 @@
              lapd/lapd_test.ok gsm0408/gsm0408_test.ok			\
              gsm0808/gsm0808_test.ok gb/bssgp_fc_tests.err		\
              gb/bssgp_fc_tests.ok gb/bssgp_fc_tests.sh			\
-             gb/gprs_bssgp_test.ok					\
-             gb/gprs_ns_test.ok kasumi/kasumi_test.ok			\
+             gb/gprs_bssgp_test.ok gb/gprs_ns_test.ok			\
+             gprs/gprs_test.ok kasumi/kasumi_test.ok			\
              msgfile/msgfile_test.ok msgfile/msgconfig.cfg		\
              logging/logging_test.ok logging/logging_test.err		\
              fr/fr_test.ok loggingrb/logging_test.ok			\
diff --git a/tests/gprs/gprs_test.c b/tests/gprs/gprs_test.c
new file mode 100644
index 0000000..be80e5c
--- /dev/null
+++ b/tests/gprs/gprs_test.c
@@ -0,0 +1,122 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include <osmocom/core/application.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/gsm/apn.h>
+
+static void apn_round_trip(const uint8_t *input, size_t len, const char *wanted_output)
+{
+	char output[len ? len : 1];
+	uint8_t encoded[len + 50];
+	char *out_str;
+	int enc_len;
+
+	/* decode and verify we have what we want */
+	out_str = osmo_apn_to_str(output, input, len);
+	OSMO_ASSERT(out_str);
+	OSMO_ASSERT(out_str == &output[0]);
+	OSMO_ASSERT(strlen(out_str) == strlen(wanted_output));
+	OSMO_ASSERT(strcmp(out_str, wanted_output) == 0);
+
+	/* encode and verify it */
+	if (len != 0) {
+		enc_len = osmo_apn_from_str(encoded, ARRAY_SIZE(encoded), wanted_output);
+		OSMO_ASSERT(enc_len == len);
+		OSMO_ASSERT(memcmp(encoded, input, enc_len) == 0);
+	} else {
+		enc_len = osmo_apn_from_str(encoded, 0, wanted_output);
+		OSMO_ASSERT(enc_len == -1);
+	}
+}
+
+static void test_gsm_03_03_apn(void)
+{
+
+	{
+		/* test invalid writes */
+		const uint8_t ref[10] = { 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF };
+		uint8_t output[10];
+		int enc_len;
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 0, "");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref, output, ARRAY_SIZE(ref)) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 0, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref, output, ARRAY_SIZE(ref)) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 1, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref + 1, output + 1, ARRAY_SIZE(ref) - 1) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 2, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref + 2, output + 2, ARRAY_SIZE(ref) - 2) == 0);
+
+		memcpy(output, ref, ARRAY_SIZE(output));
+		enc_len = osmo_apn_from_str(output, 3, "foo");
+		OSMO_ASSERT(enc_len == -1);
+		OSMO_ASSERT(memcmp(ref + 3, output + 3, ARRAY_SIZE(ref) - 3) == 0);
+	}
+
+	{
+		/* single empty label */
+		uint8_t input[] = { 0x0 };
+		const char *output = "";
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+	}
+
+	{
+		/* no label */
+		uint8_t input[] = { };
+		const char *output = "";
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+	}
+
+	{
+		/* single label with A */
+		uint8_t input[] = { 0x1, 65 };
+		const char *output = "A";
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+		OSMO_ASSERT(osmo_apn_to_str(NULL, input, ARRAY_SIZE(input) - 1) == NULL);
+	}
+
+	{
+		uint8_t input[] = { 0x3, 65, 66, 67, 0x2, 90, 122 };
+		const char *output = "ABC.Zz";
+		char tmp[strlen(output) + 1];
+		apn_round_trip(input, ARRAY_SIZE(input), output);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 1) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 2) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 4) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 5) == NULL);
+		OSMO_ASSERT(osmo_apn_to_str(tmp, input, ARRAY_SIZE(input) - 6) == NULL);
+	}
+}
+
+const struct log_info_cat default_categories[] = {
+};
+
+static struct log_info info = {
+	.cat = default_categories,
+	.num_cat = ARRAY_SIZE(default_categories),
+};
+
+int main(int argc, char **argv)
+{
+	osmo_init_logging(&info);
+
+	test_gsm_03_03_apn();
+
+	printf("Done.\n");
+	return EXIT_SUCCESS;
+}
diff --git a/tests/gprs/gprs_test.ok b/tests/gprs/gprs_test.ok
new file mode 100644
index 0000000..619c561
--- /dev/null
+++ b/tests/gprs/gprs_test.ok
@@ -0,0 +1 @@
+Done.
diff --git a/tests/testsuite.at b/tests/testsuite.at
index a542798..85c3e8b 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -84,6 +84,12 @@
 AT_CHECK([$abs_top_builddir/tests/gsm0408/gsm0408_test], [0], [expout], [ignore])
 AT_CLEANUP
 
+AT_SETUP([gprs])
+AT_KEYWORDS([gprs])
+cat $abs_srcdir/gprs/gprs_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/gprs/gprs_test], [0], [expout], [ignore])
+AT_CLEANUP
+
 AT_SETUP([logging])
 AT_KEYWORDS([logging])
 cat $abs_srcdir/logging/logging_test.ok > expout