Function TestZstdRandomJitter

gzhttp/compress_test.go:2206–2307

TestZstdRandomJitter tests that RandomJitter works with zstd using skippable frames.

(t *testing.T)

// TestZstdRandomJitter tests that RandomJitter works with zstd using skippable frames.
func TestZstdRandomJitter(t *testing.T) {
	r := httptest.NewRequest("GET", "/", nil)
	r.Header.Set("Accept-Encoding", "zstd")

	// 4KB input, incompressible to avoid compression variations.
	rng := rand.New(rand.NewSource(0))
	payload := make([]byte, 4096)
	_, err := io.ReadFull(rng, payload)
	if err != nil {
		t.Fatal(err)
	}

	// Disable gzip so we're only testing zstd
	wrapper, err := NewWrapper(RandomJitter(256, 1024, false), MinSize(10), EnableGzip(false))
	if err != nil {
		t.Fatal(err)
	}
	writePayload := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Write(payload)
	})

	// Get reference without jitter
	refWrapper, _ := NewWrapper(MinSize(10), EnableGzip(false))
	refHandler := refWrapper(writePayload)
	w := httptest.NewRecorder()
	refHandler.ServeHTTP(w, r)
	result := w.Result()
	refBody, err := io.ReadAll(result.Body)
	if err != nil {
		t.Fatal(err)
	}
	t.Logf("Reference length: %d", len(refBody))

	// Get output with jitter
	handler := wrapper(writePayload)
	w = httptest.NewRecorder()
	handler.ServeHTTP(w, r)

	result = w.Result()
	b, err := io.ReadAll(result.Body)
	if err != nil {
		t.Fatal(err)
	}

	if len(refBody) >= len(b) {
		t.Fatal("padding was not applied")
	}
	t.Logf("With jitter length: %d (padding: %d)", len(b), len(b)-len(refBody))

	// Verify the output can still be decompressed
	dec, err := zstd.NewReader(bytes.NewReader(b))
	if err != nil {
		t.Fatal(err)
	}
	decoded, err := io.ReadAll(dec)
	dec.Close()
	if err != nil {
		t.Fatal(err)