### Question:
BuiltinAggregatorUtils { public String toString(final BuiltinAggregator aggregator) { if (aggregator == null) { return translationService.getTranslation(DMNEditorConstants.DecisionTableEditor_NullBuiltinAggregator); } return aggregator.value(); } BuiltinAggregatorUtils(); @Inject  BuiltinAggregatorUtils(final TranslationService translationService); List<BuiltinAggregator> getAllValues(); String toString(final BuiltinAggregator aggregator); BuiltinAggregator toEnum(final String value);  }### Answer:
@Test public void testToString() { assertThat(builtinAggregatorUtils.toString(null)).isEqualTo(DMNEditorConstants.DecisionTableEditor_NullBuiltinAggregator); assertThat(builtinAggregatorUtils.toString(BuiltinAggregator.COUNT)).isEqualTo(BuiltinAggregator.COUNT.value()); assertThat(builtinAggregatorUtils.toString(BuiltinAggregator.MAX)).isEqualTo(BuiltinAggregator.MAX.value()); assertThat(builtinAggregatorUtils.toString(BuiltinAggregator.MIN)).isEqualTo(BuiltinAggregator.MIN.value()); assertThat(builtinAggregatorUtils.toString(BuiltinAggregator.SUM)).isEqualTo(BuiltinAggregator.SUM.value()); }