### Question:
StringSimpleFieldActions implements AtlasFieldAction { @AtlasActionProcessor public static String normalize(Normalize action, String input) { return input == null ? null : input.replaceAll("\\s+", " ").trim(); }  @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 testNormalize() { assertNull(StringSimpleFieldActions.normalize(null, null)); assertEquals("", StringSimpleFieldActions.normalize(null, "")); assertEquals("foo bar", StringSimpleFieldActions.normalize(null, " foo bar ")); assertEquals("Foo Bar", StringSimpleFieldActions.normalize(null, " Foo Bar ")); assertEquals("fOo bar", StringSimpleFieldActions.normalize(null, "fOo bar")); assertEquals("foO bar", StringSimpleFieldActions.normalize(null, " foO bar ")); assertEquals("FOO BAR", StringSimpleFieldActions.normalize(null, "\t\n FOO \f\t BAR ")); assertEquals("FOO BAR", StringSimpleFieldActions.normalize(null, "\t\n FOO \f\r BAR\f\r")); }