fix tests

rendercanvas/_loop.py

@@ -176,7 +176,7 @@ def get_canvases(self):
         schedulers = []
 
         for scheduler in self._schedulers:
-            canvas = scheduler._get_canvas()
+            canvas = scheduler.get_canvas()
             if canvas is not None:
                 canvases.append(canvas)
                 schedulers.append(scheduler)
@@ -199,7 +199,6 @@ def _tick(self):
             return
 
         # Should we stop?
-
         if not self._schedulers:
             # Stop when there are no more canvases
             self._rc_stop()
@@ -265,6 +264,9 @@ def run(self):
         if self._is_inside_run:
             raise RuntimeError("loop.run() is not reentrant.")
 
+        # Make sure that the internal timer is running, even if no canvases.
+        self._gui_timer.start(0.1)
+
         # Register interrupt handler
         prev_sig_handlers = self.__setup_interrupt()
 
@@ -448,7 +450,8 @@ def __init__(self, canvas, events, loop, *, mode="ondemand", min_fps=1, max_fps=
         # Register this scheduler/canvas at the loop object
         loop._register_scheduler(self)
 
-    def _get_canvas(self):
+    def get_canvas(self):
+        """Get the canvas, or None if it is closed or gone."""
         canvas = self._canvas_ref()
         if canvas is None or canvas.is_closed():
             # Pretty nice, we can send a close event, even if the canvas no longer exists
@@ -489,7 +492,7 @@ def _tick(self):
         self._last_tick_time = time.perf_counter()
 
         # Get canvas or stop
-        if (canvas := self._get_canvas()) is None:
+        if (canvas := self.get_canvas()) is None:
             return
 
         # Process events, handlers may request a draw

tests/test_loop.py

@@ -2,25 +2,146 @@
 Some tests for the base loop and asyncio loop.
 """
 
+import time
+import signal
 import threading
 
 from rendercanvas.asyncio import AsyncioLoop
 from testutils import run_tests
 
 
-def run_loop_briefly():
+class FakeCanvas:
+    def __init__(self, refuse_close):
+        self.refuse_close = refuse_close
+        self.is_closed = False
+
+    def _rc_close(self):
+        # Called by the loop to close a canvas
+        if not self.refuse_close:
+            self.is_closed = True
+
+
+class FakeScheduler:
+    def __init__(self, refuse_close=False):
+        self._canvas = FakeCanvas(refuse_close)
+
+    def get_canvas(self):
+        if self._canvas and not self._canvas.is_closed:
+            return self._canvas
+
+    def close_canvas(self):
+        self._canvas = None
+
+
+def test_run_loop_and_close_bc_no_canvases():
+    # Run the loop without canvas; closes immediately
+    loop = AsyncioLoop()
+    loop.call_later(0.1, print, "hi from loop!")
+    loop.run()
+
+
+def test_run_loop_and_close_canvases():
+    # After all canvases are closed, it can take one tick before its detected.
+
+    loop = AsyncioLoop()
+
+    scheduler1 = FakeScheduler()
+    scheduler2 = FakeScheduler()
+    loop._register_scheduler(scheduler1)
+    loop._register_scheduler(scheduler2)
+
+    loop.call_later(0.1, print, "hi from loop!")
+    loop.call_later(0.1, scheduler1.close_canvas)
+    loop.call_later(0.3, scheduler2.close_canvas)
+
+    t0 = time.time()
+    loop.run()
+    et = time.time() - t0
+
+    print(et)
+    assert 0.25 < et < 0.45
+
+
+def test_run_loop_and_close_with_method():
+    # Close, then wait at most one tick to close canvases, and another to conform close.
+    loop = AsyncioLoop()
+
+    scheduler1 = FakeScheduler()
+    scheduler2 = FakeScheduler()
+    loop._register_scheduler(scheduler1)
+    loop._register_scheduler(scheduler2)
+
+    loop.call_later(0.1, print, "hi from loop!")
+    loop.call_later(0.3, loop.stop)
+
+    t0 = time.time()
+    loop.run()
+    et = time.time() - t0
+
+    print(et)
+    assert 0.25 < et < 0.55
+
+
+def test_run_loop_and_interrupt():
+    # Interrupt, calls close, can take one tick to close canvases, and anoter to conform close.
+
     loop = AsyncioLoop()
+
+    scheduler1 = FakeScheduler()
+    scheduler2 = FakeScheduler()
+    loop._register_scheduler(scheduler1)
+    loop._register_scheduler(scheduler2)
+
     loop.call_later(0.1, print, "hi from loop!")
-    loop.call_later(0.2, loop.stop)
+
+    def interrupt_soon():
+        time.sleep(0.3)
+        signal.raise_signal(signal.SIGINT)
+
+    t = threading.Thread(target=interrupt_soon)
+    t.start()
+
+    t0 = time.time()
     loop.run()
+    et = time.time() - t0
+    t.join()
 
+    print(et)
+    assert 0.25 < et < 0.55
+
+
+def test_run_loop_and_interrupt_harder():
+    # In the next tick after the second interupt, it stops the loop without closing the canvases
+
+    loop = AsyncioLoop()
+
+    scheduler1 = FakeScheduler(refuse_close=True)
+    scheduler2 = FakeScheduler(refuse_close=True)
+    loop._register_scheduler(scheduler1)
+    loop._register_scheduler(scheduler2)
+
+    loop.call_later(0.1, print, "hi from loop!")
+
+    def interrupt_soon():
+        time.sleep(0.3)
+        signal.raise_signal(signal.SIGINT)
+        time.sleep(0.3)
+        signal.raise_signal(signal.SIGINT)
+
+    t = threading.Thread(target=interrupt_soon)
+    t.start()
+
+    t0 = time.time()
+    loop.run()
+    et = time.time() - t0
+    t.join()
 
-def test_loop_main():
-    run_loop_briefly()
+    print(et)
+    assert 0.6 < et < 0.75
 
 
 def test_loop_threaded():
-    t = threading.Thread(target=run_loop_briefly)
+    t = threading.Thread(target=test_run_loop_and_close_with_method)
     t.start()
     t.join()