### Question:
ListBoxValues { protected List<String> createDisplayValues(final List<String> acceptableValues) { List<String> displayValues = new ArrayList<String>(); for (String value : acceptableValues) { if (value != null) { displayValues.add(addDisplayValue(value)); } } return displayValues; } ListBoxValues(final String customPrompt,
                         final String editPrefix,
                         final ValueTester valueTester,
                         final int maxDisplayLength,
                         final boolean allowEmpty);  ListBoxValues(final String customPrompt,
                         final String editPrefix,
                         final ValueTester valueTester,
                         final int maxDisplayLength);  ListBoxValues(final String customPrompt,
                         final String editPrefix,
                         final ValueTester valueTester,
                         final boolean allowEmpty);  ListBoxValues(final String customPrompt,
                         final String editPrefix,
                         final ValueTester valueTester);  ListBoxValues(final ListBoxValues copy,
                         final boolean copyCustomValues); String getEditPrefix(); void addValues(final List<String> acceptableValues); void addValues(final Map<String, String> acceptableValues); String addCustomValue(final String newValue,
                                 final String oldValue); List<String> update(final String currentValue); List<String> getAcceptableValuesWithCustomValues(); List<String> getAcceptableValuesWithoutCustomValues(); boolean isCustomValue(final String value); String getValueForDisplayValue(final String key); String getDisplayNameForValue(final String value); String getNonCustomValueForUserString(final String userValue); String toString(); static final String EDIT_SUFFIX; }### Answer:
@Test public void testCreateDisplayValues() { List<String> acceptableValues = new ArrayList<>(); acceptableValues.add(CUSTOM_VALUE); acceptableValues.add(null); ListBoxValues processVarValues = new ListBoxValues("Constant ...", "Edit ", null); List<String> result = processVarValues.createDisplayValues(acceptableValues); assertEquals(1, result.size()); assertEquals(CUSTOM_VALUE, result.get(0)); }