Better tests of HTML delta generation

The old tests relied on deleting files and seeing them get recreated,
which could be misleading.  The new tests track which files were opened
for writing, which is more accurate.

1 files changed, 1 insertions, 1 deletions

diff --git a/coverage/html.py b/coverage/html.py
index bb519254..d5edd5f7 100644
--- a/coverage/html.py
+++ b/coverage/html.py
@@ -364,7 +364,7 @@ class HtmlStatus(object):
         usable = False
         try:
             status_file = os.path.join(directory, self.STATUS_FILE)
-            with open(status_file, "r") as fstatus:
+            with open(status_file) as fstatus:
                 status = json.load(fstatus)
         except (IOError, ValueError):
             usable = False