@Test
  public void testGetFilename() {
    assertThat(IOUtils.getFilename(null)).isNull();
    assertThat(IOUtils.getFilename("")).isEqualTo("");
    assertThat(IOUtils.getFilename("  ")).isEqualTo("  ");
    assertThat(IOUtils.getFilename(File.separator)).isEqualTo("");
    assertThat(IOUtils.getFilename("a.ext")).isEqualTo("a.ext");
    assertThat(IOUtils.getFilename(toPathname("b.ext"))).isEqualTo("b.ext");
    assertThat(IOUtils.getFilename(toPathname("path", "to", "c.ext"))).isEqualTo("c.ext");
    assertThat(IOUtils.getFilename(toPathname("export", "path", "to", "some", "filename.ext")))
        .isEqualTo("filename.ext");
    assertThat(IOUtils.getFilename(toPathname("path", "to", "a", "directory") + File.separator))
        .isEqualTo("");
  }
Gets a fully-qualified path anchored at root.
<p>

@param pathElements a String array containing the elements of the path.
@return a fully-qualified pathname as a String value.
geode-core/src/test/java/org/apache/geode/internal/util/IOUtilsJUnitTest.java