tests: Don't overwrite mkstemp, just check environment

Since this can interfere with the initrdinject test

virtinst/connection.py

@@ -35,13 +35,6 @@ from virtinst.cli import VirtOptionString
 _virtinst_uri_magic = "__virtinst_test__"
 
 
-def _fakemkstemp(prefix, *args, **kwargs):
-    ignore = args
-    ignore = kwargs
-    filename = os.path.join(".", prefix)
-    return os.open(filename, os.O_RDWR | os.O_CREAT), filename
-
-
 def _sanitize_xml(xml):
     import difflib
 
@@ -411,8 +404,6 @@ class VirtualConnection(object):
 
         if "predictable" in opts:
             opts.pop("predictable")
-            import tempfile
-            tempfile.mkstemp = _fakemkstemp
             setattr(self, "_virtinst__fake_conn_predictable", True)
 
         # Fake remote status

virtinst/urlfetcher.py

@@ -63,8 +63,15 @@ class _ImageFetcher(object):
     def saveTemp(self, fileobj, prefix):
         if not os.path.exists(self.scratchdir):
             os.makedirs(self.scratchdir, 0750)
-        (fd, fn) = tempfile.mkstemp(prefix="virtinst-" + prefix,
-                                    dir=self.scratchdir)
+
+        prefix = "virtinst-" + prefix
+        if "VIRTINST_TEST_SUITE" in os.environ:
+            fn = os.path.join(".", prefix)
+            fd = os.open(fn, os.O_RDWR | os.O_CREAT)
+        else:
+            (fd, fn) = tempfile.mkstemp(prefix=prefix,
+                                        dir=self.scratchdir)
+
         block_size = 16384
         try:
             while 1: