### Question:
StringSimpleFieldActions implements AtlasFieldAction { @AtlasActionProcessor public static String separateByDash(SeparateByDash action, String input) { if (input == null || input.length() == 0) { return input; } return STRING_SEPARATOR_PATTERN.matcher(input).replaceAll("-"); }  @AtlasActionProcessor static String capitalize(Capitalize action, String input); @AtlasActionProcessor static String fileExtension(FileExtension action, String input); @AtlasActionProcessor static String lowercase(Lowercase action, String input); @AtlasActionProcessor static Character lowercaseChar(LowercaseChar action, Character input); @AtlasActionProcessor static String normalize(Normalize action, String input); @AtlasActionProcessor static String removeFileExtension(RemoveFileExtension action, String input); @AtlasActionProcessor static String separateByDash(SeparateByDash action, String input); @AtlasActionProcessor static String separateByUnderscore(SeparateByUnderscore action, String input); @AtlasActionProcessor static String trim(Trim action, String input); @AtlasActionProcessor static String trimLeft(TrimLeft action, String input); @AtlasActionProcessor static String trimRight(TrimRight action, String input); @AtlasActionProcessor static String uppercase(Uppercase action, String input); @AtlasActionProcessor static Character uppercaseChar(UppercaseChar action, Character input); static final String STRING_SEPARATOR_REGEX; static final Pattern STRING_SEPARATOR_PATTERN; }### Answer:
@Test public void testSeparateByDash() { assertNull(StringSimpleFieldActions.separateByDash(new SeparateByDash(), null)); assertEquals("", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "")); assertEquals("-", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "-")); assertEquals("foo", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "foo")); assertEquals("foo-bar", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "foo bar")); assertEquals("foo-bar", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "foo+bar")); assertEquals("foo-bar", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "foo=bar")); assertEquals("foo-bar", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "foo:bar")); assertEquals("f-o-o-b-a-r", StringSimpleFieldActions.separateByDash(new SeparateByDash(), "f:o:o:b:a:r")); }