t.Errorf("CutSuffix(%q, %q) = %q, %v, want %q, %v", tt.s, tt.sep, before, found, tt.before, tt.found)
		}
	}
}

func makeBenchInputHard() string {
	tokens := [...]string{
		"<a>", "<p>", "<b>", "<strong>",
		"</a>", "</p>", "</b>", "</strong>",
		"hello", "world",
	}
	x := make([]byte, 0, 1<<20)
	for {

	b.ResetTimer()
	for _, test := range tests {
		b.Run(test.name, func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				ToValidUTF8(test.input, replacement)
			}
		})
	}
}

func makeBenchInputHard() []byte {
	tokens := [...]string{
		"<a>", "<p>", "<b>", "<strong>",
		"</a>", "</p>", "</b>", "</strong>",
		"hello", "world",
	}
	x := make([]byte, 0, 1<<20)
	for {