suite.addTest(
        MapTestSuiteBuilder.using(
                new TestMapGenerator<Range<Integer>, String>() {
                  @Override
                  public SampleElements<Entry<Range<Integer>, String>> samples() {
                    return new SampleElements<>(
                        mapEntry(Range.singleton(0), "banana"),
                        mapEntry(Range.closedOpen(3, 5), "frisbee"),

        result.put(entry.getKey(), entry.getValue());
      }
      return result;
    }

    @Override
    public SampleElements<Entry<Country, String>> samples() {
      return new SampleElements<>(
          immutableEntry(Country.CANADA, "DOLLAR"),
          immutableEntry(Country.CHILE, "PESO"),
          immutableEntry(Country.UK, "POUND"),

        result.put(entry.getKey(), entry.getValue());
      }
      return result;
    }

    @Override
    public SampleElements<Entry<Country, Currency>> samples() {
      return new SampleElements<>(
          mapEntry(Country.CANADA, Currency.DOLLAR),
          mapEntry(Country.CHILE, Currency.PESO),
          mapEntry(Country.UK, Currency.POUND),

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ObjectArrays;
import com.google.common.collect.testing.ListTestSuiteBuilder;
import com.google.common.collect.testing.SampleElements;
import com.google.common.collect.testing.TestListGenerator;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;