FileLink: add test with path-like object

FileLink supports path-like objects on Python >= 3.6, so we should test this scenario as well.

IPython/lib/tests/test_display.py

@@ -14,6 +14,11 b''
 #-----------------------------------------------------------------------------
 from tempfile import NamedTemporaryFile, mkdtemp
 from os.path import split, join as pjoin, dirname
+import sys
+try:
+    import pathlib
+except ImportError:
+    pass
 
 # Third-party imports
 import nose.tools as nt
@@ -33,6 +38,9 b' from IPython.testing.decorators import skipif_not_numpy'
 def test_instantiation_FileLink():
     """FileLink: Test class can be instantiated"""
     fl = display.FileLink('example.txt')
+    # TODO: remove if when only Python >= 3.6 is supported
+    if sys.version_info >= (3, 6):
+        fl = display.FileLink(pathlib.PurePath('example.txt'))
 
 def test_warning_on_non_existant_path_FileLink():
     """FileLink: Calling _repr_html_ on non-existant files returns a warning