repo = repo.withUrl("http://xxx.xxx.com");
        model2 = Settings.newBuilder()
                .profiles(List.of(prof.withRepositories(List.of(repo))))
                .build();
        problems.clear();
        problems = validator.validate(model2);
        assertEquals(1, problems.size());

        repo = repo.withId("xxx");
        model2 = Settings.newBuilder()

          <version>4.0.0+</version>
          <description>
            The frequency for downloading updates - can be
            {@code always},
            {@code daily} (default),
            {@code interval:XXX} (in minutes) or
            {@code never} (only if it doesn't exist locally).
          </description>
          <type>String</type>
        </field>
        <field>
          <name>checksumPolicy</name>

        <field>
          <name>updatePolicy</name>
          <version>1.0.0+</version>
          <description>
            The frequency for downloading updates - can be "always",
            "daily" (default), "interval:XXX" (in minutes) or "never"
            (only if it doesn't exist locally).
          </description>
          <type>String</type>
        </field>
        <field>
          <name>checksumPolicy</name>

            return true;
        }
    }

    private boolean isValidProfileId(String id) {
        switch (id.charAt(0)) { // avoid first character that has special CLI meaning in "mvn -P xxx"
            case '+': // activate
            case '-': // deactivate
            case '!': // deactivate
            case '?': // optional
                return false;
            default:
        }