diff --git a/contrib/filter-repo-demos/lint-history b/contrib/filter-repo-demos/lint-history
index 2f8d3e5..a9630c6 100755
--- a/contrib/filter-repo-demos/lint-history
+++ b/contrib/filter-repo-demos/lint-history
@@ -114,7 +114,7 @@ def lint_with_real_filenames(commit, metadata):
         f.write(contents_plus_newline[:-1])
 
       # Lint the file
-      subprocess.check_call(lint_args.command + [filename])
+      subprocess.check_call(lint_args.command + [filename.decode('utf-8')])
 
       # Get the new contents
       with open(filename, "rb") as f:
diff --git a/t/t9391-filter-repo-lib-usage.sh b/t/t9391-filter-repo-lib-usage.sh
index a79d768..25bc986 100755
--- a/t/t9391-filter-repo-lib-usage.sh
+++ b/t/t9391-filter-repo-lib-usage.sh
@@ -4,7 +4,14 @@ test_description='Usage of git-filter-repo as a library'
 . ./test-lib.sh
 
 # for git_filter_repo.py import
-export PYTHONPATH=$(dirname $TEST_DIRECTORY):$PYTHONPATH
+case "$(uname -s)" in
+MINGW*|MSYS)
+	export PYTHONPATH=$(cygpath -am $TEST_DIRECTORY/..)\;$PYTHONPATH
+	;;
+*)
+	export PYTHONPATH=$(dirname $TEST_DIRECTORY):$PYTHONPATH
+	;;
+esac
 # Avoid writing git_filter_repo.pyc file
 export PYTHONDONTWRITEBYTECODE=1
 export CONTRIB_DIR=$TEST_DIRECTORY/../contrib/filter-repo-demos