diff --git a/test/unit/core/test_ip4_route.c b/test/unit/core/test_ip4_route.c
index 9034ccf6..c4db482c 100644
--- a/test/unit/core/test_ip4_route.c
+++ b/test/unit/core/test_ip4_route.c
@@ -38,7 +38,7 @@ typedef enum {
     PACKET_PBUF_REF
 } packet_type_t;
 
-unsigned char *packet_buffer[1518];
+static unsigned char *packet_buffer[1518];
 static int random_mock = -1;
 /* Mock the esp-random to return 0 for easier result checking */
 uint32_t esp_random(void) 
diff --git a/test/unit/ip6/test_ip6_route.c b/test/unit/ip6/test_ip6_route.c
index 95eb331c..abead58e 100644
--- a/test/unit/ip6/test_ip6_route.c
+++ b/test/unit/ip6/test_ip6_route.c
@@ -20,7 +20,7 @@ static int ap_cnt = 0;
 static int sta_cnt = 0;
 static u8_t ap_output_p_type_internal = (PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS | PBUF_TYPE_ALLOC_SRC_MASK_STD_HEAP);
 static u8_t sta_output_p_type_internal = (PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS | PBUF_TYPE_ALLOC_SRC_MASK_STD_HEAP);
-unsigned char packet_buffer[sizeof(struct ip6_hdr) + IP6_PAYLOAD_LEN];
+static unsigned char packet_buffer[sizeof(struct ip6_hdr) + IP6_PAYLOAD_LEN];
 
 /* Setups/teardown functions */
 static void