diff --git a/tests/sys/sys/Makefile b/tests/sys/sys/Makefile
index eed87935e6e..95739c12763 100644
--- a/tests/sys/sys/Makefile
+++ b/tests/sys/sys/Makefile
@@ -6,8 +6,6 @@ TESTSDIR=	${TESTSBASE}/sys/sys
 
 ATF_TESTS_C=	arb_test bitstring_test qmath_test rb_test splay_test
 
-WARNS?=	5
-
 .if ${COMPILER_TYPE} == "gcc"
 CFLAGS.bitstring_test=	-fno-strict-overflow
 .endif
diff --git a/tests/sys/sys/arb_test.c b/tests/sys/sys/arb_test.c
index 9cf3f205268..adbd7794e6f 100644
--- a/tests/sys/sys/arb_test.c
+++ b/tests/sys/sys/arb_test.c
@@ -41,7 +41,7 @@ struct node {
 	int key;
 };
 
-ARB32_HEAD(tree, node) *root;
+static ARB32_HEAD(tree, node) *root;
 
 static int
 compare(const struct node *a, const struct node *b)
diff --git a/tests/sys/sys/rb_test.c b/tests/sys/sys/rb_test.c
index 287422ccf90..c558ad6098c 100644
--- a/tests/sys/sys/rb_test.c
+++ b/tests/sys/sys/rb_test.c
@@ -39,7 +39,7 @@ struct node {
 	int key;
 };
 
-RB_HEAD(tree, node) root;
+static RB_HEAD(tree, node) root;
 
 static int
 compare(struct node *a, struct node *b)
diff --git a/tests/sys/sys/splay_test.c b/tests/sys/sys/splay_test.c
index 9b14c7c855c..f0cf4ecd5eb 100644
--- a/tests/sys/sys/splay_test.c
+++ b/tests/sys/sys/splay_test.c
@@ -39,7 +39,7 @@ struct node {
 	int key;
 };
 
-SPLAY_HEAD(tree, node) root;
+static SPLAY_HEAD(tree, node) root;
 
 static int
 compare(struct node *a, struct node *b)