@Test
  public void testAppendToPath() {
    assertThat(IOUtils.appendToPath(null, (String[]) null)).isNull();
    assertThat(IOUtils.appendToPath(null)).isEqualTo(File.separator);
    assertThat(IOUtils.appendToPath("")).isEqualTo(File.separator);
    assertThat(IOUtils.appendToPath(" ")).isEqualTo(File.separator);
    assertThat(IOUtils.appendToPath(File.separator)).isEqualTo(File.separator);
    assertThat(IOUtils.appendToPath(null, "bin", "a.out")).isEqualTo(toPathname("bin", "a.out"));
    assertThat(IOUtils.appendToPath(File.separator, "bin", "a.out"))
        .isEqualTo(toPathname("bin", "a.out"));
    assertThat(IOUtils.appendToPath(toPathname("usr", "local"), "bin", "a.out"))
        .isEqualTo(toPathname("usr", "local", "bin", "a.out"));
  }
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