Example script for ineterminate progress bar with a long running comp…

…utation (pyapp-kit#579)

docs/examples/progress_bars/README.md

@@ -1,3 +1,3 @@
-# Progress bars examples
+# Progress bar examples
 
 Examples of progress bars in magicgui.

docs/examples/progress_bars/progress_indeterminate.py

@@ -0,0 +1,31 @@
+"""# Indeterminate progress bar
+
+Example of an indeterminate progress bar for a long running computation
+of unknown time.
+
+"""
+import time
+
+from superqt.utils import thread_worker
+
+from magicgui import magicgui
+from magicgui.tqdm import tqdm
+
+
+@magicgui(call_button=True, layout="horizontal")
+def long_running(sleep_time=5):
+    """Long running computation with an indeterminate progress bar."""
+    # Here tqdm is not provided an iterable argument, or the 'total' kwarg
+    # so it cannot calculate the expected number of iterations
+    # which means it will create an indeterminate progress bar
+    with tqdm() as pbar:
+        # It is best practice to use a separate thread for long running computations
+        # This makes the function non-blocking, you can still interact with the widget
+        @thread_worker(connect={"finished": lambda: pbar.progressbar.hide()})
+        def sleep(secs):
+            time.sleep(secs)
+
+        sleep(sleep_time)
+
+
+long_running.show(run=True)

tests/test_tqdm.py

@@ -19,6 +19,15 @@ def test_tqdm_outside_of_functiongui():
     assert tuple(trange(5)) == tuple(range(5))
 
 
+def test_indeterminate_tqdm_outside_of_functiongui():
+    """Test that we can have tqdm with an indeterminate total range."""
+    with tqdm(total=None) as pbar:
+        assert pbar.total is None
+        assert pbar.n == 0
+        pbar.update()
+        assert pbar.n == 1
+
+
 def test_disabled_tqdm():
     """Test that a disabled tqdm does not have a progressbar or magicgui."""
 
@@ -137,6 +146,21 @@ def long_func(steps=2):
     assert len(long_func._tqdm_pbars) == 1
 
 
+def test_indeterminate_tqdm_inside_magicgui():
+    """Test that we can have tqdm with an indeterminate total range."""
+
+    @magicgui
+    def long_func():
+        """Long running computation with indeterminate range."""
+        with tqdm(total=None):
+            pass
+
+    long_func.show()
+    assert not long_func._tqdm_pbars
+    long_func()
+    assert len(long_func._tqdm_pbars) == 1
+
+
 def _indirectly_decorated(steps=2):
     for _i in trange(4):
         pass