Fix black tiles on connect; 64px tiles, byte-based delta choice

test_e2e_wire.py

@@ -10,10 +10,12 @@ import struct
 import subprocess
 import sys
 import time
+from io import BytesIO
 
 import urllib.request
 
 import websockets
+from PIL import Image
 
 
 def get_json(url, timeout=10):
@@ -47,8 +49,6 @@ async def run():
                 continue
             assert t == 0, f"expected full frame, got type {t}"
             assert h["w"] == h["h"] == 1024
-            from io import BytesIO
-            from PIL import Image
             img = Image.open(BytesIO(payload)); img.load()
             assert img.size == (1024, 1024), img.size
             full_bytes = len(payload)
@@ -83,6 +83,24 @@ async def run():
                 break
         assert saw, "no frame after Text2OS"
 
+    # 3.5) a late-joining client must receive the WHOLE desktop, not just the
+    # tiles the cursor happens to dirty. Regression: "black tiles until
+    # mouseover" -- the shared delta stream left new sockets almost blank.
+    await asyncio.sleep(0.5)
+    async with websockets.connect(WS, max_size=None) as late:
+        deadline = time.time() + 10
+        got_full = None
+        while time.time() < deadline:
+            t, h, payload = unpack(await asyncio.wait_for(late.recv(), 10))
+            if t == 2:
+                continue
+            got_full = t
+            break
+        assert got_full == 0, f"late client got frame type {got_full}, want full(0)"
+        img = Image.open(BytesIO(payload)); img.load()
+        assert img.size == (1024, 1024), img.size
+        kinds.append("late_full")
+
     # 4) metrics endpoint
     m = get_json(f"{BASE}/metrics")
     print("FULL bytes:", full_bytes)