Add js web stuff to landing page + documentation

go/jsbundler/hmr_ws_test.go

@@ -0,0 +1,67 @@
+//go:build dev
+
+package jsbundler
+
+import (
+	"bufio"
+	"bytes"
+	"testing"
+)
+
+// The canonical handshake vector from RFC 6455 §1.3.
+func TestComputeAccept(t *testing.T) {
+	got := computeAccept("dGhlIHNhbXBsZSBub25jZQ==")
+	const want = "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="
+	if got != want {
+		t.Fatalf("computeAccept = %q, want %q", got, want)
+	}
+}
+
+// A masked client frame round-trips through readFrame (payload unmasked, opcode
+// preserved) — the path exercised when the browser sends a ping or close.
+func TestReadFrameMaskedText(t *testing.T) {
+	payload := []byte("hello hmr")
+	mask := [4]byte{0x12, 0x34, 0x56, 0x78}
+
+	var buf bytes.Buffer
+	buf.WriteByte(0x80 | opText)             // FIN + text
+	buf.WriteByte(0x80 | byte(len(payload))) // MASK + len
+	buf.Write(mask[:])
+	for i, b := range payload {
+		buf.WriteByte(b ^ mask[i%4])
+	}
+
+	op, got, err := readFrame(bufio.NewReader(&buf))
+	if err != nil {
+		t.Fatalf("readFrame: %v", err)
+	}
+	if op != opText {
+		t.Errorf("opcode = %#x, want %#x", op, opText)
+	}
+	if !bytes.Equal(got, payload) {
+		t.Errorf("payload = %q, want %q", got, payload)
+	}
+}
+
+// A server frame is written unmasked and parses back to the same payload.
+func TestWriteFrameRoundTrip(t *testing.T) {
+	payload := bytes.Repeat([]byte("x"), 300) // exercises the 16-bit length path
+	var raw bytes.Buffer
+	c := &wsClient{brw: bufio.NewReadWriter(bufio.NewReader(nil), bufio.NewWriter(&raw))}
+	if err := c.writeText(payload); err != nil {
+		t.Fatalf("writeText: %v", err)
+	}
+	if raw.Bytes()[0] != (0x80 | opText) {
+		t.Fatalf("first byte = %#x, want %#x", raw.Bytes()[0], 0x80|opText)
+	}
+	if raw.Bytes()[1]&0x80 != 0 {
+		t.Fatalf("server frame must not set the mask bit")
+	}
+	op, got, err := readFrame(bufio.NewReader(&raw))
+	if err != nil {
+		t.Fatalf("readFrame: %v", err)
+	}
+	if op != opText || !bytes.Equal(got, payload) {
+		t.Errorf("round-trip mismatch: op=%#x len=%d", op, len(got))
+	}
+}