This test incorrectly assumes that the root user is always available.
However, in the build environment, the root user is not available.
Note that because the original file distributed in the release on PyPi
has lines ending in CRLF, those are retained in the diff below.

--- a/pyfakefs/tests/fake_filesystem_test.py	1969-12-31 16:00:00.000000000 -0800
+++ b/pyfakefs/tests/fake_filesystem_test.py	1969-12-31 16:00:00.000000000 -0800
@@ -1021,15 +1021,6 @@
             self.assertEqual(self.path.expanduser('~'),
                              self.os.environ['HOME'].replace('/', '!'))
 
-    @unittest.skipIf(TestCase.is_windows or TestCase.is_cygwin,
-                     'only tested on unix systems')
-    def test_expand_root(self):
-        if sys.platform == 'darwin':
-            roothome = '!var!root'
-        else:
-            roothome = '!root'
-        self.assertEqual(self.path.expanduser('~root'), roothome)
-
     def test_getsize_path_nonexistent(self):
         file_path = 'foo!bar!baz'
         self.assertRaises(os.error, self.path.getsize, file_path)
6de68cac98c6a228dde3db9d5'>refs</a><a class='active' href='/guix/log/tests/base32.scm'>log</a><a href='/guix/tree/tests/base32.scm?id=e37144e79d899156de68cac98c6a228dde3db9d5'>tree</a><a href='/guix/commit/tests/base32.scm?id=e37144e79d899156de68cac98c6a228dde3db9d5'>commit</a><a href='/guix/diff/tests/base32.scm?id=e37144e79d899156de68cac98c6a228dde3db9d5'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/base32.scm'>
<input type='hidden' name='id' value='e37144e79d899156de68cac98c6a228dde3db9d5'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=e37144e79d899156de68cac98c6a228dde3db9d5'>root</a>/<a href='/guix/log/tests?id=e37144e79d899156de68cac98c6a228dde3db9d5'>tests</a>/<a href='/guix/log/tests/base32.scm?id=e37144e79d899156de68cac98c6a228dde3db9d5'>base32.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/base32.scm?id=e37144e79d899156de68cac98c6a228dde3db9d5&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-08-29 16:24:17 +0200'>2020-08-29</span></td><td><a href='/guix/commit/tests/base32.scm?id=d7965b58d25c9c7648ba5682223f32d759fdffda'>build: Remove references to the 'nix-hash' program.</a><span class='msg-avail'>...<span class='msg-tooltip'>* configure.ac: Remove check for 'nix-hash'.
* tests/base32.scm (%nix-hash, %have-nix-hash?): Remove.
("sha256 &amp; bytevector-&gt;nix-base32-string"): Remove test.
* build-aux/pre-inst-env.in: Do not set 'NIX_HASH' environment
variable.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-09-04 17:25:11 +0200'>2018-09-04</span></td><td><a href='/guix/commit/tests/base32.scm?id=ca719424455465fca4b872c371daf2a46de88b33'>Switch to Guile-Gcrypt.</a><span class='msg-avail'>...<span class='msg-tooltip'>This removes (guix hash) and (guix pk-crypto), which now live as part of
Guile-Gcrypt (version 0.1.0.)

* guix/gcrypt.scm, guix/hash.scm, guix/pk-crypto.scm,
tests/hash.scm, tests/pk-crypto.scm: Remove.
* configure.ac: Test for Guile-Gcrypt.  Remove LIBGCRYPT and
LIBGCRYPT_LIBDIR assignments.
* m4/guix.m4 (GUIX_ASSERT_LIBGCRYPT_USABLE): Remove.
* README: Add Guile-Gcrypt to the dependencies; move libgcrypt as
"required unless --disable-daemon".
* doc/guix.texi (Requirements): Likewise.
* gnu/packages/bash.scm, guix/derivations.scm, guix/docker.scm,
guix/git.scm, guix/http-client.scm, guix/import/cpan.scm,
guix/import/cran.scm, guix/import/crate.scm, guix/import/elpa.scm,
guix/import/gnu.scm, guix/import/hackage.scm,
guix/import/texlive.scm, guix/import/utils.scm, guix/nar.scm,
guix/pki.scm, guix/scripts/archive.scm,
guix/scripts/authenticate.scm, guix/scripts/download.scm,
guix/scripts/hash.scm, guix/scripts/pack.scm,
guix/scripts/publish.scm, guix/scripts/refresh.scm,
guix/scripts/substitute.scm, guix/store.scm,
guix/store/deduplication.scm, guix/tests.scm, tests/base32.scm,
tests/builders.scm, tests/challenge.scm, tests/cpan.scm,
tests/crate.scm, tests/derivations.scm, tests/gem.scm,
tests/nar.scm, tests/opam.scm, tests/pki.scm,
tests/publish.scm, tests/pypi.scm, tests/store-deduplication.scm,
tests/store.scm, tests/substitute.scm: Adjust imports.
* gnu/system/vm.scm: Likewise.
(guile-sqlite3&amp;co): Rename to...
(gcrypt-sqlite3&amp;co): ... this.  Add GUILE-GCRYPT.
(expression-&gt;derivation-in-linux-vm)[config]: Remove.
(iso9660-image)[config]: Remove.
(qemu-image)[config]: Remove.
(system-docker-image)[config]: Remove.
* guix/scripts/pack.scm: Adjust imports.
(guile-sqlite3&amp;co): Rename to...
(gcrypt-sqlite3&amp;co): ... this.  Add GUILE-GCRYPT.
(self-contained-tarball)[build]: Call 'make-config.scm' without
 #:libgcrypt argument.
(squashfs-image)[libgcrypt]: Remove.
[build]: Call 'make-config.scm' without #:libgcrypt.
(docker-image)[config, json]: Remove.
[build]: Add GUILE-GCRYPT to the extensions  Remove (guix config) from
the imported modules.
* guix/self.scm (specification-&gt;package): Remove "libgcrypt", add
"guile-gcrypt".
(compiled-guix): Remove #:libgcrypt.
[guile-gcrypt]: New variable.
[dependencies]: Add it.
[*core-modules*]: Remove #:libgcrypt from 'make-config.scm' call.
Add #:extensions.
[*config*]: Remove #:libgcrypt from 'make-config.scm' call.
(%dependency-variables): Remove %libgcrypt.
(make-config.scm): Remove #:libgcrypt.
* build-aux/build-self.scm (guile-gcrypt): New variable.
(make-config.scm): Remove #:libgcrypt.
(build-program)[fake-gcrypt-hash]: New variable.
Add (gcrypt hash) to the imported modules.  Adjust load path
assignments.
* gnu/packages/package-management.scm (guix)[propagated-inputs]: Add
GUILE-GCRYPT.
[arguments]: In 'wrap-program' phase, add GUILE-GCRYPT to the search
path.
</span></span></td><td>Ludovic Courtès</td></tr>