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

--- thefuck-3.15/tests/test_conf.py
+++ thefuck-3.15/tests/test_conf.py
@@ -12,7 +12,7 @@
 
 @pytest.fixture
 def environ(monkeypatch):
-    data = {}
+    data = {"HOME": os.environ.get("HOME")}
     monkeypatch.setattr('thefuck.conf.os.environ', data)
     return data
 
