### Question:
Strings { public static String capitalize(String string) { return string == null ? null : string.substring( 0, 1 ).toUpperCase( Locale.ROOT ) + string.substring( 1 ); } private  Strings(); static String capitalize(String string); static String decapitalize(String string); static String join(Iterable<?> iterable, String separator); static String join(Iterable<T> iterable, String separator, Extractor<T, String> extractor); static String joinAndCamelize(Iterable<?> iterable); static boolean isEmpty(String string); static boolean isNotEmpty(String string); static String getSafeVariableName(String name, String... existingVariableNames); static String getSafeVariableName(String name, Collection<String> existingVariableNames); static String sanitizeIdentifierName(String identifier); static String stubPropertyName(String fullyQualifiedName); static String getMostSimilarWord(String word, Collection<String> similarWords);  }### Answer:
@Test public void testCapitalize() { assertThat( Strings.capitalize( null ) ).isNull(); assertThat( Strings.capitalize( "c" ) ).isEqualTo( "C" ); assertThat( Strings.capitalize( "capitalize" ) ).isEqualTo( "Capitalize" ); assertThat( Strings.capitalize( "AlreadyCapitalized" ) ).isEqualTo( "AlreadyCapitalized" ); assertThat( Strings.capitalize( "notCapitalized" ) ).isEqualTo( "NotCapitalized" ); }
@Test public void capitalizeEnglish() { Locale.setDefault( Locale.ENGLISH ); String international = Strings.capitalize( "international" ); assertThat( international ).isEqualTo( "International" ); }
@Test public void capitalizeTurkish() { Locale.setDefault( TURKEY_LOCALE ); String international = Strings.capitalize( "international" ); assertThat( international ).isEqualTo( "International" ); }