### Question:
TextNode extends LeafNode { public boolean isBlank() { return StringUtil.isBlank(coreValue()); } TextNode(String text);  TextNode(String text, String baseUri); String nodeName(); String text(); TextNode text(String text); String getWholeText(); boolean isBlank(); TextNode splitText(int offset); @Override String toString(); static TextNode createFromEncoded(String encodedText, String baseUri); static TextNode createFromEncoded(String encodedText);  }### Answer:
@Test public void testBlank() { TextNode one = new TextNode(""); TextNode two = new TextNode(" "); TextNode three = new TextNode(" \n\n "); TextNode four = new TextNode("Hello"); TextNode five = new TextNode(" \nHello "); assertTrue(one.isBlank()); assertTrue(two.isBlank()); assertTrue(three.isBlank()); assertFalse(four.isBlank()); assertFalse(five.isBlank()); }