diff --git a/psutil/tests/test_unicode.py b/psutil/tests/test_unicode.py
index bbb763f31..c2a2f8479 100755
--- a/psutil/tests/test_unicode.py
+++ b/psutil/tests/test_unicode.py
@@ -207,7 +207,7 @@ def test_proc_cwd(self):
     def test_proc_open_files(self):
         p = psutil.Process()
         start = set(p.open_files())
-        with open(self.funky_name, 'wb'):
+        with open(self.funky_name, 'rb'):
             new = set(p.open_files())
         path = (new - start).pop().path
         self.assertIsInstance(path, str)
diff --git a/scripts/internal/generate_manifest.py b/scripts/internal/generate_manifest.py
index 8b6b4f5fa..3511b7492 100755
--- a/scripts/internal/generate_manifest.py
+++ b/scripts/internal/generate_manifest.py
@@ -12,6 +12,10 @@
 import subprocess
 
 
+IGNORED_EXTS = ('.png', '.jpg', '.jpeg')
+IGNORED_FILES = ('.travis.yml', 'appveyor.yml')
+
+
 def sh(cmd):
     return subprocess.check_output(
         cmd, shell=True, universal_newlines=True).strip()
@@ -21,8 +25,8 @@ def main():
     files = sh("git ls-files").split('\n')
     for file in files:
         if file.startswith('.ci/') or \
-                os.path.splitext(file)[1] in ('.png', '.jpg') or \
-                file in ('.travis.yml', 'appveyor.yml'):
+                os.path.splitext(file)[1].lower() in IGNORED_EXTS or \
+                file in IGNORED_FILES:
             continue
         print("include " + file)