diff --git a/tests/gnrc_sixlowpan_frag/Makefile b/tests/gnrc_sixlowpan_frag/Makefile
new file mode 100644
index 0000000000..6ccd891884
--- /dev/null
+++ b/tests/gnrc_sixlowpan_frag/Makefile
@@ -0,0 +1,19 @@
+include ../Makefile.tests_common
+
+BOARD_INSUFFICIENT_MEMORY := arduino-duemilanove arduino-uno nucleo-f031k6
+
+USEMODULE += gnrc_sixlowpan_frag
+USEMODULE += embunit
+
+# GNRC modules should not be initialized unless we want to
+DISABLE_MODULE += auto_init
+
+# we don't need all this packet buffer space so reduce it a little
+CFLAGS += -DTEST_SUITES -DGNRC_PKTBUF_SIZE=2048
+
+# to be able to include gnrc_sixlowpan_frag-internal `rbuf.h`
+INCLUDES += -I$(RIOTBASE)/sys/net/gnrc/network_layer/sixlowpan/frag/
+
+TEST_ON_CI_WHITELIST += all
+
+include $(RIOTBASE)/Makefile.include
diff --git a/tests/gnrc_sixlowpan_frag/main.c b/tests/gnrc_sixlowpan_frag/main.c
new file mode 100644
index 0000000000..f68a846e09
--- /dev/null
+++ b/tests/gnrc_sixlowpan_frag/main.c
@@ -0,0 +1,578 @@
+/*
+ * Copyright (C) 2015 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       Tests extension header handling of gnrc stack.
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ * @author      Takuo Yonezawa <Yonezawa-T2@mail.dnp.co.jp>
+ *
+ * @}
+ */
+
+#include "embUnit.h"
+#include "net/gnrc/pktbuf.h"
+#include "net/gnrc/netreg.h"
+#include "rbuf.h"
+#include "xtimer.h"
+
+#define TEST_NETIF_HDR_SRC      { 0xb3, 0x47, 0x60, 0x49, \
+                                  0x78, 0xfe, 0x95, 0x48 }
+#define TEST_NETIF_HDR_DST      { 0xa4, 0xf2, 0xd2, 0xc9, \
+                                  0x13, 0xb9, 0xbb, 0x25 }
+#define TEST_NETIF_IFACE        (9)
+#define TEST_TAG                (0x690e)
+#define TEST_PAGE               (0)
+#define TEST_RECEIVE_TIMEOUT    (100U)
+#define TEST_GC_TIMEOUT         (RBUF_TIMEOUT + TEST_RECEIVE_TIMEOUT)
+
+/* test date taken from an experimental run (uncompressed ICMPv6 echo reply with
+ * 300 byte payload)*/
+#define TEST_DATAGRAM_SIZE      (348U)
+#ifdef MODULE_GNRC_IPV6
+#define TEST_DATAGRAM_NETTYPE   (GNRC_NETTYPE_IPV6)
+#else  /* MODULE_GNRC_IPV6 */
+#define TEST_DATAGRAM_NETTYPE   (GNRC_NETTYPE_UNDEF)
+#endif /* MODULE_GNRC_IPV6 */
+#define TEST_FRAGMENT1_OFFSET   (0U)
+#define TEST_FRAGMENT2_OFFSET   (96U)
+#define TEST_FRAGMENT3_OFFSET   (192U)
+#define TEST_FRAGMENT4_OFFSET   (288U)
+#define TEST_FRAGMENT1 { \
+        0xc1, 0x5c, 0x00, 0x05, 0x41, 0x60, 0x00, 0x00, \
+        0x00, 0x01, 0x34, 0x3a, 0x40, 0xfe, 0x80, 0x00, \
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x7b, 0x65, 0x08, \
+        0x22, 0x86, 0x93, 0x9d, 0x5a, 0xfe, 0x80, 0x00, \
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x7b, 0x79, 0x7f, \
+        0x7f, 0xa4, 0xb1, 0x55, 0x2e, 0x81, 0x00, 0x7a, \
+        0x81, 0x00, 0x54, 0x00, 0x02, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54                    \
+    }
+#define TEST_FRAGMENT2 { \
+        0xe1, 0x5c, 0x00, 0x05, 0x0c, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54                    \
+    }
+#define TEST_FRAGMENT3 { \
+        0xe1, 0x5c, 0x00, 0x05, 0x18, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54                    \
+    }
+#define TEST_FRAGMENT4 { \
+        0xe1, 0x5c, 0x00, 0x05, 0x24, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54                                            \
+}
+#define TEST_DATAGRAM { \
+        0x60, 0x00, 0x00, 0x00, 0x01, 0x34, 0x3a, 0x40, \
+        0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+        0x7b, 0x65, 0x08, 0x22, 0x86, 0x93, 0x9d, 0x5a, \
+        0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+        0x7b, 0x79, 0x7f, 0x7f, 0xa4, 0xb1, 0x55, 0x2e, \
+        0x81, 0x00, 0x7a, 0x81, 0x00, 0x54, 0x00, 0x02, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, 0x54, \
+        0x54, 0x54, 0x54, 0x54 \
+}
+
+static const uint8_t _test_netif_hdr_src[] = TEST_NETIF_HDR_SRC;
+static const uint8_t _test_netif_hdr_dst[] = TEST_NETIF_HDR_SRC;
+static struct {
+    gnrc_netif_hdr_t hdr;
+    uint8_t src[GNRC_NETIF_HDR_L2ADDR_MAX_LEN];
+    uint8_t dst[GNRC_NETIF_HDR_L2ADDR_MAX_LEN];
+} _test_netif_hdr;
+
+static uint8_t _fragment1[] = TEST_FRAGMENT1;
+static uint8_t _fragment2[] = TEST_FRAGMENT2;
+static uint8_t _fragment3[] = TEST_FRAGMENT3;
+static uint8_t _fragment4[] = TEST_FRAGMENT4;
+static const uint8_t _datagram[] = TEST_DATAGRAM;
+static msg_t _msg_queue;
+
+static inline void _set_fragment_tag(void *frag, uint16_t tag)
+{
+    sixlowpan_frag_t *f = frag;
+
+    f->tag = byteorder_htons(tag);
+}
+
+static inline void _set_fragment_offset(void *frag, uint16_t offset)
+{
+    sixlowpan_frag_n_t *f = frag;
+
+    TEST_ASSERT_EQUAL_INT(SIXLOWPAN_FRAG_N_DISP,
+                          f->disp_size.u8[0] & SIXLOWPAN_FRAG_DISP_MASK);
+    f->offset = offset / 8;
+}
+
+static void _set_up(void)
+{
+    rbuf_reset();
+    gnrc_pktbuf_init();
+    gnrc_netif_hdr_init(&_test_netif_hdr.hdr,
+                        GNRC_NETIF_HDR_L2ADDR_MAX_LEN,
+                        GNRC_NETIF_HDR_L2ADDR_MAX_LEN);
+    _test_netif_hdr.hdr.if_pid = TEST_NETIF_IFACE;
+    gnrc_netif_hdr_set_src_addr(&_test_netif_hdr.hdr,
+                                (uint8_t *)_test_netif_hdr_src,
+                                sizeof(_test_netif_hdr_src));
+    gnrc_netif_hdr_set_dst_addr(&_test_netif_hdr.hdr,
+                                (uint8_t *)_test_netif_hdr_dst,
+                                sizeof(_test_netif_hdr_dst));
+    _set_fragment_tag(_fragment1, TEST_TAG);
+    _set_fragment_tag(_fragment2, TEST_TAG);
+    _set_fragment_tag(_fragment3, TEST_TAG);
+    _set_fragment_tag(_fragment4, TEST_TAG);
+    _set_fragment_offset(_fragment2, TEST_FRAGMENT2_OFFSET);
+    _set_fragment_offset(_fragment3, TEST_FRAGMENT3_OFFSET);
+    _set_fragment_offset(_fragment4, TEST_FRAGMENT4_OFFSET);
+}
+
+static const rbuf_t *_first_non_empty_rbuf(void)
+{
+    const rbuf_t *rbuf = rbuf_array();
+
+    for (unsigned i = 0; i < RBUF_SIZE; i++) {
+        if (!rbuf_entry_empty(&rbuf[i])) {
+            return rbuf;
+        }
+    }
+    return NULL;
+}
+
+static void _test_entry(const rbuf_t *entry, unsigned exp_current_size,
+                        unsigned exp_int_start, unsigned exp_int_end)
+{
+    TEST_ASSERT_NOT_NULL(entry);
+    TEST_ASSERT_NOT_NULL(entry->super.pkt);
+    TEST_ASSERT_EQUAL_INT(TEST_DATAGRAM_SIZE, entry->super.pkt->size);
+    TEST_ASSERT_EQUAL_INT(sizeof(_test_netif_hdr_src),
+                          entry->super.src_len);
+    TEST_ASSERT_MESSAGE(memcmp(entry->super.src, _test_netif_hdr_src,
+                               entry->super.src_len) == 0,
+                        "entry->super.src != TEST_NETIF_HDR_SRC");
+    TEST_ASSERT_EQUAL_INT(sizeof(_test_netif_hdr_dst),
+                          entry->super.dst_len);
+    TEST_ASSERT_MESSAGE(memcmp(entry->super.dst, _test_netif_hdr_dst,
+                               entry->super.dst_len) == 0,
+                        "entry->super.dst != TEST_NETIF_HDR_DST");
+    TEST_ASSERT_EQUAL_INT(TEST_TAG, entry->super.tag);
+    TEST_ASSERT_EQUAL_INT(exp_current_size, entry->super.current_size);
+    TEST_ASSERT_NOT_NULL(entry->ints);
+    TEST_ASSERT_NULL(entry->ints->next);
+    TEST_ASSERT_EQUAL_INT(exp_int_start, entry->ints->start);
+    TEST_ASSERT_EQUAL_INT(exp_int_end, entry->ints->end);
+}
+
+static void _check_pktbuf(const rbuf_t *entry)
+{
+    if (entry != NULL) {
+        gnrc_pktbuf_release(entry->super.pkt);
+    }
+    TEST_ASSERT_MESSAGE(gnrc_pktbuf_is_empty(), "Packet buffer is not empty");
+}
+
+static void test_rbuf_add__success_first_fragment(void)
+{
+    gnrc_pktsnip_t *pkt = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                                          GNRC_NETTYPE_SIXLOWPAN);
+    const rbuf_t *entry;
+
+    TEST_ASSERT_NOT_NULL(pkt);
+    rbuf_add(&_test_netif_hdr.hdr, pkt, TEST_FRAGMENT1_OFFSET, TEST_PAGE);
+    entry = _first_non_empty_rbuf();
+    /* current_size must be the offset of fragment 2, not the size of
+     * fragment 1 (fragment dispatch was removed, IPHC was applied etc.). */
+    _test_entry(entry, TEST_FRAGMENT2_OFFSET,
+                TEST_FRAGMENT1_OFFSET, TEST_FRAGMENT2_OFFSET - 1);
+    _check_pktbuf(entry);
+}
+
+static void test_rbuf_add__success_subsequent_fragment(void)
+{
+    gnrc_pktsnip_t *pkt = gnrc_pktbuf_add(NULL, _fragment2, sizeof(_fragment2),
+                                          GNRC_NETTYPE_SIXLOWPAN);
+    const rbuf_t *entry;
+
+    TEST_ASSERT_NOT_NULL(pkt);
+    rbuf_add(&_test_netif_hdr.hdr, pkt, TEST_FRAGMENT2_OFFSET, TEST_PAGE);
+    entry = _first_non_empty_rbuf();
+    /* current_size must be the offset of fragment 3, not the size of
+     * fragment 2 (fragment dispatch was removed, IPHC was applied etc.). */
+    _test_entry(entry, TEST_FRAGMENT3_OFFSET - TEST_FRAGMENT2_OFFSET,
+                TEST_FRAGMENT2_OFFSET, TEST_FRAGMENT3_OFFSET - 1);
+    _check_pktbuf(entry);
+}
+
+static void test_rbuf_add__success_duplicate_fragments(void)
+{
+    gnrc_pktsnip_t *pkt1 = gnrc_pktbuf_add(NULL, _fragment3, sizeof(_fragment3),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    gnrc_pktsnip_t *pkt2 = gnrc_pktbuf_add(NULL, _fragment3, sizeof(_fragment3),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    const rbuf_t *entry;
+
+    TEST_ASSERT_NOT_NULL(pkt1);
+    rbuf_add(&_test_netif_hdr.hdr, pkt1, TEST_FRAGMENT3_OFFSET, TEST_PAGE);
+    TEST_ASSERT_NOT_NULL(pkt2);
+    rbuf_add(&_test_netif_hdr.hdr, pkt2, TEST_FRAGMENT3_OFFSET, TEST_PAGE);
+    entry = _first_non_empty_rbuf();
+    /* current_size must be the offset of fragment 4, not the size of
+     * fragment 3 (fragment dispatch was removed, IPHC was applied etc.). */
+    _test_entry(entry, TEST_FRAGMENT4_OFFSET - TEST_FRAGMENT3_OFFSET,
+                TEST_FRAGMENT3_OFFSET, TEST_FRAGMENT4_OFFSET - 1);
+    _check_pktbuf(entry);
+}
+
+static void test_rbuf_add__success_complete(void)
+{
+    gnrc_pktsnip_t *pkt1 = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    gnrc_pktsnip_t *pkt2 = gnrc_pktbuf_add(NULL, _fragment2, sizeof(_fragment2),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    gnrc_pktsnip_t *pkt3 = gnrc_pktbuf_add(NULL, _fragment3, sizeof(_fragment3),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    gnrc_pktsnip_t *pkt4 = gnrc_pktbuf_add(NULL, _fragment4, sizeof(_fragment4),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    gnrc_pktsnip_t *datagram;
+    msg_t msg = { .type = 0U };
+    gnrc_netreg_entry_t reg = GNRC_NETREG_ENTRY_INIT_PID(
+            GNRC_NETREG_DEMUX_CTX_ALL,
+            sched_active_pid
+        );
+
+    gnrc_netreg_register(TEST_DATAGRAM_NETTYPE, &reg);
+    /* Mixing up things. Order decided by fair dice-rolls ;-) */
+    TEST_ASSERT_NOT_NULL(pkt2);
+    rbuf_add(&_test_netif_hdr.hdr, pkt2, TEST_FRAGMENT2_OFFSET, TEST_PAGE);
+    TEST_ASSERT_NOT_NULL(pkt4);
+    rbuf_add(&_test_netif_hdr.hdr, pkt4, TEST_FRAGMENT4_OFFSET, TEST_PAGE);
+    TEST_ASSERT_NOT_NULL(pkt1);
+    rbuf_add(&_test_netif_hdr.hdr, pkt1, TEST_FRAGMENT1_OFFSET, TEST_PAGE);
+    TEST_ASSERT_NOT_NULL(pkt3);
+    rbuf_add(&_test_netif_hdr.hdr, pkt3, TEST_FRAGMENT3_OFFSET, TEST_PAGE);
+    TEST_ASSERT_MESSAGE(
+            xtimer_msg_receive_timeout(&msg, TEST_RECEIVE_TIMEOUT) >= 0,
+            "Receiving reassembled datagram timed out"
+        );
+    gnrc_netreg_unregister(TEST_DATAGRAM_NETTYPE, &reg);
+    TEST_ASSERT_EQUAL_INT(GNRC_NETAPI_MSG_TYPE_RCV, msg.type);
+    TEST_ASSERT_NOT_NULL(msg.content.ptr);
+    datagram = msg.content.ptr;
+    TEST_ASSERT_EQUAL_INT(TEST_DATAGRAM_SIZE, datagram->size);
+    TEST_ASSERT_EQUAL_INT(TEST_DATAGRAM_NETTYPE, datagram->type);
+    TEST_ASSERT_MESSAGE(memcmp(_datagram, datagram->data,
+                        TEST_DATAGRAM_SIZE) == 0,
+                        "Reassembled datagram does not contain expected data");
+    gnrc_pktbuf_release(datagram);
+    _check_pktbuf(NULL);
+}
+
+static void test_rbuf_add__full_rbuf(void)
+{
+    gnrc_pktsnip_t *pkt;
+    const rbuf_t *rbuf;
+
+    for (unsigned i = 0; i < RBUF_SIZE; i++) {
+        pkt = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                              GNRC_NETTYPE_SIXLOWPAN);
+        TEST_ASSERT_NOT_NULL(pkt);
+        rbuf_add(&_test_netif_hdr.hdr, pkt, TEST_FRAGMENT1_OFFSET,
+                 TEST_PAGE);
+        _set_fragment_tag(_fragment1, TEST_TAG + i + 1);
+        /* pkt is released in rbuf_add() */
+    }
+    pkt = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                          GNRC_NETTYPE_SIXLOWPAN);
+    TEST_ASSERT_NOT_NULL(pkt);
+    rbuf_add(&_test_netif_hdr.hdr, pkt, TEST_FRAGMENT1_OFFSET,
+             TEST_PAGE);
+    rbuf = rbuf_array();
+    for (unsigned i = 0; i < RBUF_SIZE; i++) {
+        const rbuf_t *entry = &rbuf[i];
+
+        TEST_ASSERT_MESSAGE(!rbuf_entry_empty(entry),
+                            "Reassembly buffer entry unexpectedly empty");
+        TEST_ASSERT((sizeof(_fragment1) - sizeof(sixlowpan_frag_t)) <
+                    entry->super.pkt->size);
+        TEST_ASSERT_MESSAGE(
+                memcmp(entry->super.pkt->data,
+                       &_fragment1[sizeof(sixlowpan_frag_t)],
+                       sizeof(_fragment1) - sizeof(sixlowpan_frag_t)) != 0,
+                "Reassembly buffer contains fragment that was not supposed "
+                "to fit");
+        /* releasing pkt to check if packet buffer is empty in the end */
+        gnrc_pktbuf_release(entry->super.pkt);
+    }
+    _check_pktbuf(NULL);
+}
+
+static void test_rbuf_add__too_big_fragment(void)
+{
+    gnrc_pktsnip_t *pkt = gnrc_pktbuf_add(NULL, _fragment1,
+                                          /* something definetely bigger than
+                                           * the datagram size noted in
+                                           * _fragment1, can't just be + 1,
+                                           * since fragment dispatch and other
+                                           * dispatches are supposed to be
+                                           * subtracted */
+                                          2 * TEST_DATAGRAM_SIZE,
+                                          GNRC_NETTYPE_SIXLOWPAN);
+
+    TEST_ASSERT_NOT_NULL(pkt);
+    rbuf_add(&_test_netif_hdr.hdr, pkt, TEST_FRAGMENT1_OFFSET,
+             TEST_PAGE);
+    /* packet buffer is empty*/
+    TEST_ASSERT_NULL(_first_non_empty_rbuf());
+    _check_pktbuf(NULL);
+}
+
+static void test_rbuf_add__overlap_lhs(void)
+{
+    static const size_t pkt2_offset = TEST_FRAGMENT2_OFFSET - 8U;
+    gnrc_pktsnip_t *pkt1 = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    gnrc_pktsnip_t *pkt2;
+    const rbuf_t *rbuf;
+    unsigned rbuf_entries = 0;
+
+    _set_fragment_offset(_fragment2, pkt2_offset);
+    pkt2 = gnrc_pktbuf_add(NULL, _fragment2, sizeof(_fragment2),
+                           GNRC_NETTYPE_SIXLOWPAN);
+    TEST_ASSERT_NOT_NULL(pkt1);
+    rbuf_add(&_test_netif_hdr.hdr, pkt1, TEST_FRAGMENT1_OFFSET,
+             TEST_PAGE);
+    TEST_ASSERT_NOT_NULL(pkt2);
+    rbuf_add(&_test_netif_hdr.hdr, pkt2, pkt2_offset, TEST_PAGE);
+    rbuf = rbuf_array();
+    for (unsigned i = 0; i < RBUF_SIZE; i++) {
+        const rbuf_t *entry = &rbuf[i];
+        if (!rbuf_entry_empty(entry)) {
+            static const size_t pkt3_offset = TEST_FRAGMENT3_OFFSET - 8U - 1;
+
+            rbuf_entries++;
+            /* only _fragment2 should now in the reassembly buffer according to
+             * https://tools.ietf.org/html/rfc4944#section-5.3 */
+            _test_entry(entry,
+                        /* current_size must be the offset of fragment 3, not
+                         * the size of fragment 2 (fragment dispatch was
+                         * removed, IPHC was applied etc.). */
+                        TEST_FRAGMENT3_OFFSET - TEST_FRAGMENT2_OFFSET,
+                        (unsigned)pkt2_offset, (unsigned)pkt3_offset);
+            /* releasing pkt to check if packet buffer is empty in the end */
+            gnrc_pktbuf_release(entry->super.pkt);
+        }
+    }
+    TEST_ASSERT_EQUAL_INT(1U, rbuf_entries);
+    _check_pktbuf(NULL);
+}
+
+static void test_rbuf_add__overlap_rhs(void)
+{
+    static const size_t pkt2_offset = TEST_FRAGMENT2_OFFSET + 8U;
+    gnrc_pktsnip_t *pkt1 = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    gnrc_pktsnip_t *pkt2;
+    gnrc_pktsnip_t *pkt3 = gnrc_pktbuf_add(NULL, _fragment3, sizeof(_fragment3),
+                                           GNRC_NETTYPE_SIXLOWPAN);
+    const rbuf_t *rbuf;
+    unsigned rbuf_entries = 0;
+
+    _set_fragment_offset(_fragment2, pkt2_offset);
+    pkt2 = gnrc_pktbuf_add(NULL, _fragment2, sizeof(_fragment2),
+                           GNRC_NETTYPE_SIXLOWPAN);
+    TEST_ASSERT_NOT_NULL(pkt1);
+    rbuf_add(&_test_netif_hdr.hdr, pkt1, TEST_FRAGMENT1_OFFSET,
+             TEST_PAGE);
+    TEST_ASSERT_NOT_NULL(pkt3);
+    rbuf_add(&_test_netif_hdr.hdr, pkt3, TEST_FRAGMENT3_OFFSET, TEST_PAGE);
+    TEST_ASSERT_NOT_NULL(pkt2);
+    rbuf_add(&_test_netif_hdr.hdr, pkt2, pkt2_offset, TEST_PAGE);
+    rbuf = rbuf_array();
+    for (unsigned i = 0; i < RBUF_SIZE; i++) {
+        const rbuf_t *entry = &rbuf[i];
+        if (!rbuf_entry_empty(entry)) {
+            static const size_t pkt3_offset = TEST_FRAGMENT3_OFFSET + 8U - 1U;
+
+            rbuf_entries++;
+            /* only _fragment2 should now in the reassembly buffer according to
+             * https://tools.ietf.org/html/rfc4944#section-5.3 */
+            _test_entry(entry,
+                        /* current_size must be the offset of fragment 3, not
+                         * the size of fragment 2 (fragment dispatch was
+                         * removed, IPHC was applied etc.). */
+                        TEST_FRAGMENT3_OFFSET - TEST_FRAGMENT2_OFFSET,
+                        (unsigned)pkt2_offset, (unsigned)pkt3_offset);
+            /* releasing pkt to check if packet buffer is empty in the end */
+            gnrc_pktbuf_release(entry->super.pkt);
+        }
+    }
+    TEST_ASSERT_EQUAL_INT(1U, rbuf_entries);
+    _check_pktbuf(NULL);
+}
+
+static void test_rbuf_rm(void)
+{
+    const rbuf_t *entry;
+
+    test_rbuf_add__success_first_fragment();
+    entry = _first_non_empty_rbuf();
+    /* entry is however not properly removed yet */
+    TEST_ASSERT_NOT_NULL(entry);
+    /* intentionally discarding const qualifier since we enter rbuf's internal
+     * context again */
+    rbuf_rm((rbuf_t *)entry);
+    /* reassembly buffer is now empty */
+    TEST_ASSERT_NULL(_first_non_empty_rbuf());
+    _check_pktbuf(NULL);
+}
+
+static void test_rbuf_gc__manually(void)
+{
+    gnrc_pktsnip_t *pkt = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                                          GNRC_NETTYPE_SIXLOWPAN);
+    rbuf_t *entry;
+
+    TEST_ASSERT_NOT_NULL(pkt);
+    rbuf_add(&_test_netif_hdr.hdr, pkt, TEST_FRAGMENT1_OFFSET, TEST_PAGE);
+    /* discarding const qualifier intentionally to override `arrival` */
+    entry = (rbuf_t *)_first_non_empty_rbuf();
+    TEST_ASSERT_NOT_NULL(entry);
+    /* set arrival RBUF_TIMEOUT into the past */
+    entry->arrival -= RBUF_TIMEOUT;
+    rbuf_gc();
+    /* reassembly buffer is now empty */
+    TEST_ASSERT_NULL(_first_non_empty_rbuf());
+    _check_pktbuf(NULL);
+}
+
+static void test_rbuf_gc__timed(void)
+{
+    msg_t msg;
+    gnrc_pktsnip_t *pkt = gnrc_pktbuf_add(NULL, _fragment1, sizeof(_fragment1),
+                                          GNRC_NETTYPE_SIXLOWPAN);
+    rbuf_t *entry;
+
+    TEST_ASSERT_NOT_NULL(pkt);
+    rbuf_add(&_test_netif_hdr.hdr, pkt, TEST_FRAGMENT1_OFFSET, TEST_PAGE);
+    /* discarding const qualifier intentionally to override `arrival` */
+    entry = (rbuf_t *)_first_non_empty_rbuf();
+    TEST_ASSERT_NOT_NULL(entry);
+    TEST_ASSERT_MESSAGE(
+            xtimer_msg_receive_timeout(&msg, TEST_GC_TIMEOUT) >= 0,
+            "Waiting for GC timer timed out"
+        );
+    TEST_ASSERT_EQUAL_INT(GNRC_SIXLOWPAN_MSG_FRAG_GC_RBUF, msg.type);
+    rbuf_gc();
+    /* reassembly buffer is now empty */
+    TEST_ASSERT_NULL(_first_non_empty_rbuf());
+    _check_pktbuf(NULL);
+}
+
+static void run_unittests(void)
+{
+    EMB_UNIT_TESTFIXTURES(fixtures) {
+        new_TestFixture(test_rbuf_add__success_first_fragment),
+        new_TestFixture(test_rbuf_add__success_subsequent_fragment),
+        new_TestFixture(test_rbuf_add__success_duplicate_fragments),
+        new_TestFixture(test_rbuf_add__success_complete),
+        new_TestFixture(test_rbuf_add__full_rbuf),
+        new_TestFixture(test_rbuf_add__too_big_fragment),
+        new_TestFixture(test_rbuf_add__overlap_lhs),
+        new_TestFixture(test_rbuf_add__overlap_rhs),
+        new_TestFixture(test_rbuf_rm),
+        new_TestFixture(test_rbuf_gc__manually),
+        new_TestFixture(test_rbuf_gc__timed),
+    };
+
+    EMB_UNIT_TESTCALLER(sixlo_frag_tests, _set_up, NULL, fixtures);
+    TESTS_START();
+    TESTS_RUN((Test *)&sixlo_frag_tests);
+    TESTS_END();
+}
+
+int main(void)
+{
+    /* no auto-init, so xtimer needs to be initialized manually*/
+    xtimer_init();
+    /* netreg requires queue, but queue size one should be enough for us */
+    msg_init_queue(&_msg_queue, 1U);
+    run_unittests();
+    return 0;
+}
diff --git a/tests/gnrc_sixlowpan_frag/tests/01-run.py b/tests/gnrc_sixlowpan_frag/tests/01-run.py
new file mode 100755
index 0000000000..1dcdd41c14
--- /dev/null
+++ b/tests/gnrc_sixlowpan_frag/tests/01-run.py
@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2019 Freie Universität Berlin
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+import sys
+from testrunner import run
+
+
+def testfunc(child):
+    child.expect(r'OK \(\d+ tests\)')
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc))