Retain environment setting of "HOME" for tests that need os.path.expanduser()
to return a readable directory in the build chroot.

--- thefuck-3.25/tests/conftest.py
+++ thefuck-3.25/tests/conftest.py
@@ -64,6 +64,7 @@ def set_shell(monkeypatch):
 
 @pytest.fixture(autouse=True)
 def os_environ(monkeypatch):
-    env = {'PATH': os.environ['PATH']}
+    env = {'PATH': os.environ['PATH'],
+           'HOME': os.environ['HOME']}
     monkeypatch.setattr('os.environ', env)
     return env
ex</a> : <a href='/guix/'>guix</a></td><td class='form'><form method='get'>
<input type='hidden' name='id' value='9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'>refs</a><a class='active' href='/guix/log/TODO'>log</a><a href='/guix/tree/TODO?id=9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'>tree</a><a href='/guix/commit/TODO?id=9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'>commit</a><a href='/guix/diff/TODO?id=9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/TODO'>
<input type='hidden' name='id' value='9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'/><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=9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'>root</a>/<a href='/guix/log/TODO?id=9321cf7f51eb6dc3fe49d4302eed4e47a52284e2'>TODO</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/TODO?id=9321cf7f51eb6dc3fe49d4302eed4e47a52284e2&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>