@Test
  public void testIsNotAvailableFromProvider() throws IOException {
    URI uri = fs.getUri();
    assertEquals(fs, FileSystems.getFileSystem(uri));

    fs.close();

    try {
      FileSystems.getFileSystem(uri);
      fail();
    } catch (FileSystemNotFoundException expected) {
    }
  }
Tests for what happens when a file system is closed.

@author Colin Decker
jimfs/src/test/java/com/google/common/jimfs/JimfsFileSystemCloseTest.java