func TestClean(t *testing.T) {
	tests := []struct {
		path   string
		expVal string
	}{
		{
			path:   "../../../readme.txt",
			expVal: "readme.txt",
		},
		{
			path:   "a/../../../readme.txt",
			expVal: "readme.txt",
		},
		{
			path:   "/../a/b/../c/../readme.txt",
			expVal: "a/readme.txt",
		},
		{
			path:   "/a/readme.txt",
			expVal: "a/readme.txt",
		},
		{
			path:   "/",
			expVal: "",
		},

		{
			path:   "/a/b/c/readme.txt",
			expVal: "a/b/c/readme.txt",
		},
	}
	for _, test := range tests {
		t.Run("", func(t *testing.T) {
			assert.Equal(t, test.expVal, Clean(test.path))
		})
	}
}
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.