### Question:
SecurePasswordField extends TextField { @Override public CharSequence getCharacters() { return CharBuffer.wrap(content, 0, length); } SecurePasswordField();  SecurePasswordField(@NamedArg("placeholderChar") String placeholderChar); void cut(); void copy(); Object queryAccessibleAttribute(AccessibleAttribute attribute, Object... parameters); @Override void replaceText(int start, int end, String text); @Override CharSequence getCharacters(); void setPassword(CharSequence password); void setPassword(char[] password); void wipe(); ReadOnlyBooleanProperty capsLockedProperty(); boolean isCapsLocked(); ReadOnlyBooleanProperty containingNonPrintableCharsProperty(); boolean isContainingNonPrintableChars(); BooleanProperty revealPasswordProperty(); boolean isRevealPassword(); void setRevealPassword(boolean revealPassword);  }### Answer:
@Test @DisplayName("entering NFC string leads to NFC char[]") public void enterNfcString() { pwField.appendText("str\u00F6m"); pwField.insertText(0, "\u212Bng"); pwField.appendText("\uD83D\uDCA9"); CharSequence result = pwField.getCharacters(); Assertions.assertEquals('\u00C5', result.charAt(0)); Assertions.assertEquals('n', result.charAt(1)); Assertions.assertEquals('g', result.charAt(2)); Assertions.assertEquals('s', result.charAt(3)); Assertions.assertEquals('t', result.charAt(4)); Assertions.assertEquals('r', result.charAt(5)); Assertions.assertEquals('ö', result.charAt(6)); Assertions.assertEquals('m', result.charAt(7)); Assertions.assertEquals('\uD83D', result.charAt(8)); Assertions.assertEquals('\uDCA9', result.charAt(9)); }
@Test @DisplayName("entering NFD string leads to NFC char[]") public void enterNfdString() { pwField.appendText("str\u006F\u0308m"); pwField.insertText(0, "\u0041\u030Ang"); pwField.appendText("\uD83D\uDCA9"); CharSequence result = pwField.getCharacters(); Assertions.assertEquals('\u00C5', result.charAt(0)); Assertions.assertEquals('n', result.charAt(1)); Assertions.assertEquals('g', result.charAt(2)); Assertions.assertEquals('s', result.charAt(3)); Assertions.assertEquals('t', result.charAt(4)); Assertions.assertEquals('r', result.charAt(5)); Assertions.assertEquals('ö', result.charAt(6)); Assertions.assertEquals('m', result.charAt(7)); Assertions.assertEquals('\uD83D', result.charAt(8)); Assertions.assertEquals('\uDCA9', result.charAt(9)); }