diff --git a/lib/isc/tests/lex_test.c b/lib/isc/tests/lex_test.c
index cb485f6706..ca3f97f9a5 100644
--- a/lib/isc/tests/lex_test.c
+++ b/lib/isc/tests/lex_test.c
@@ -56,6 +56,10 @@ lex_0xff(void **state) {
 
 	result = isc_lex_gettoken(lex, 0, &token);
 	assert_int_equal(result, ISC_R_SUCCESS);
+
+	isc_lex_destroy(&lex);
+
+	isc_mem_destroy(&mctx);
 }
 
 /* check setting of source line */
@@ -100,6 +104,10 @@ lex_setline(void **state) {
 
 	line = isc_lex_getsourceline(lex);
 	assert_int_equal(line, 105U);
+
+	isc_lex_destroy(&lex);
+
+	isc_mem_destroy(&mctx);
 }
 
 int