### Question:
StringSimpleFieldActions implements AtlasFieldAction { @AtlasActionProcessor public static String lowercase(Lowercase action, String input) { if (input == null) { return null; } return input.toLowerCase(); }  @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 testLowerCase() { assertNull(StringSimpleFieldActions.lowercase(new Lowercase(), null)); assertEquals("", StringSimpleFieldActions.lowercase(new Lowercase(), "")); assertEquals("foo", StringSimpleFieldActions.lowercase(new Lowercase(), "foo")); assertEquals("foo", StringSimpleFieldActions.lowercase(new Lowercase(), "Foo")); assertEquals("foo", StringSimpleFieldActions.lowercase(new Lowercase(), "fOo")); assertEquals("foo", StringSimpleFieldActions.lowercase(new Lowercase(), "foO")); assertEquals("foo", StringSimpleFieldActions.lowercase(new Lowercase(), "FOO")); assertEquals("foo bar", StringSimpleFieldActions.lowercase(new Lowercase(), "FOO BAR")); }