tests MAINTENANCE char overflow
diff --git a/tests/utests/basic/test_common.c b/tests/utests/basic/test_common.c
index cf01c96..75235a2 100644
--- a/tests/utests/basic/test_common.c
+++ b/tests/utests/basic/test_common.c
@@ -26,30 +26,30 @@
 
     /* test invalid UTF-8 characters in lyxml_getutf8
      * - https://en.wikipedia.org/wiki/UTF-8 */
-    buf[0] = 0x04;
+    buf[0] = (char)0x04;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
-    buf[0] = 0x80;
+    buf[0] = (char)0x80;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
 
-    buf[0] = 0xc0;
-    buf[1] = 0x00;
+    buf[0] = (char)0xc0;
+    buf[1] = (char)0x00;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
-    buf[1] = 0x80;
+    buf[1] = (char)0x80;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
 
-    buf[0] = 0xe0;
-    buf[1] = 0x00;
-    buf[2] = 0x80;
+    buf[0] = (char)0xe0;
+    buf[1] = (char)0x00;
+    buf[2] = (char)0x80;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
-    buf[1] = 0x80;
+    buf[1] = (char)0x80;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
 
-    buf[0] = 0xf0;
-    buf[1] = 0x00;
-    buf[2] = 0x80;
-    buf[3] = 0x80;
+    buf[0] = (char)0xf0;
+    buf[1] = (char)0x00;
+    buf[2] = (char)0x80;
+    buf[3] = (char)0x80;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
-    buf[1] = 0x80;
+    buf[1] = (char)0x80;
     assert_int_equal(LY_EINVAL, ly_getutf8(&str, &c, &len));
 }
 
diff --git a/tests/utests/types/binary.c b/tests/utests/types/binary.c
index 556e0b4..2df1cc9 100644
--- a/tests/utests/types/binary.c
+++ b/tests/utests/types/binary.c
@@ -47,7 +47,7 @@
 test_plugin_store(void **state)
 {
     const char *val, *dec_val;
-    char bin_val[2];
+    unsigned char bin_val[2];
     struct ly_err_item *err = NULL;
     struct lys_module *mod;
     struct lyd_value value = {0};