@Override
    boolean putIfAbsent(String name, Mapping mapping) {
        return storage().putIfAbsent(name, mapping) == null;
    }
@Test
    public void when_putIfAbsent_then_doesNotOverwrite() {
        String name = randomName();

        assertThat(storage.putIfAbsent(name, mapping(name, "type-1"))).isTrue();
        assertThat(storage.putIfAbsent(name, mapping(name, "type-2"))).isFalse();
        assertTrue(storage.allObjects().stream().anyMatch(m -> m instanceof Mapping && ((Mapping) m).connectorType().equals("type-1")));
        assertTrue(storage.allObjects().stream().noneMatch(m -> m instanceof Mapping && ((Mapping) m).connectorType().equals("type-2")));
    }