TESTS: Add tests that medium changing commands fail for readonly devices

test-tool/iscsi-test-cu.h

@@ -83,6 +83,8 @@ void test_readcapacity10_simple(void);
 void test_readcapacity16_simple(void);
 void test_readcapacity16_alloclen(void);
 
+void test_readonly_sbc(void);
+
 void test_testunitready_simple(void);
 
 void test_unmap_simple(void);