diff --git a/tests/tests-c-compiler/check-src/check-60.c b/tests/tests-c-compiler/check-src/check-60.c
index 23bdac1..f7e84ca 100644
--- a/tests/tests-c-compiler/check-src/check-60.c
+++ b/tests/tests-c-compiler/check-src/check-60.c
@@ -17,7 +17,9 @@
 	unsigned char *b, *bend;
 	(void)app_key;
 	assert(buf_offset + size < sizeof(buf));
-	memcpy(buf + buf_offset, buffer, size);
+	if (buffer) {
+		memcpy(buf + buf_offset, buffer, size);
+	}
 	b = buf + buf_offset;
 	bend = b + size;
 	printf("=> [");
diff --git a/tests/tests-c-compiler/check-src/check-62.c b/tests/tests-c-compiler/check-src/check-62.c
index 560929c..762be1a 100644
--- a/tests/tests-c-compiler/check-src/check-62.c
+++ b/tests/tests-c-compiler/check-src/check-62.c
@@ -33,7 +33,9 @@
 	unsigned char *b, *bend;
 	(void)app_key;
 	assert(buf_offset + size < sizeof(buf));
-	memcpy(buf + buf_offset, buffer, size);
+	if (buffer) {
+		memcpy(buf + buf_offset, buffer, size);
+	}
 	b = buf + buf_offset;
 	bend = b + size;
 	printf("=> [");