public String namespaces() {
    return SLASH.join("v1", prefix, "namespaces");
  }
@Test
  public void testNamespaces() {
    assertThat(withPrefix.namespaces()).isEqualTo("v1/ws/catalog/namespaces");
    assertThat(withoutPrefix.namespaces()).isEqualTo("v1/namespaces");
  }