@Test
  public void testPrefixFilter() throws IOException {
    String filterString = " PrefixFilter('row' ) ";
    PrefixFilter prefixFilter = doTestFilter(filterString, PrefixFilter.class);
    byte[] prefix = prefixFilter.getPrefix();
    assertEquals("row", new String(prefix, StandardCharsets.UTF_8));

    filterString = " PrefixFilter(row)";
    try {
      doTestFilter(filterString, PrefixFilter.class);
      assertTrue(false);
    } catch (IllegalArgumentException e) {
      System.out.println(e.getMessage());
    }
  }
This class tests ParseFilter.java It tests the entire work flow from when a string is given by
the user and how it is parsed to construct the corresponding Filter object
hbase-server/src/test/java/org/apache/hadoop/hbase/filter/TestParseFilter.java