### Question:
DocumentationParser extends AbstractIndexedParser<AbstractDocumentation> { @Override public boolean canParse(final String line) { if (line == null) { throw new IllegalArgumentException("Line cannot be null."); } return isCommentStart(line); }  @Override boolean canParse(final String line); @Override AbstractDocumentation parse(final int startingIndex, final List<String> lines);  }### Answer:
@Test public void testCanParseNullLine() { IllegalArgumentException e = assertThrows(IllegalArgumentException.class, () -> { parser.canParse(null); }); assertThat(e.getMessage()).isEqualTo("Line cannot be null."); }