package proxy

import "testing"

func TestNormalizeChunkBasicProgression(t *testing.T) {
	prev := ""

	if got := normalizeChunk("abc", &prev); got != "abc" {
		t.Fatalf("expected first chunk to pass through, got %q", got)
	}
	if got := normalizeChunk("abcde", &prev); got != "de" {
		t.Fatalf("expected appended delta, got %q", got)
	}
}

func TestNormalizeChunkPrefixRewindDoesNotReplay(t *testing.T) {
	prev := ""

	_ = normalizeChunk("abcde", &prev)
	if got := normalizeChunk("abc", &prev); got != "" {
		t.Fatalf("expected rewind chunk to be ignored, got %q", got)
	}
	if prev != "abcde" {
		t.Fatalf("expected previous snapshot to remain longest version, got %q", prev)
	}
	if got := normalizeChunk("abcdef", &prev); got != "f" {
		t.Fatalf("expected only unseen suffix after rewind, got %q", got)
	}
}

func TestNormalizeChunkOverlapDelta(t *testing.T) {
	prev := "hello world"

	if got := normalizeChunk("world!!!", &prev); got != "!!!" {
		t.Fatalf("expected overlap suffix delta, got %q", got)
	}
}