tests: Add test_window_basic

This test just makes sure that created windows match the default
WindowProperties (with a few exceptions).

This also adds the following fixtures:

  * graphics_engine - scope='session', GraphicsEngine
  * graphics_pipe - scope='session', default GraphicsPipe
  * window - scope='test', GraphicsWindow with default framebuffer and window properties

tests/display/conftest.py

@@ -0,0 +1,42 @@
+import pytest
+
+@pytest.fixture
+def graphics_pipe(scope='session'):
+    from panda3d.core import GraphicsPipeSelection
+
+    pipe = GraphicsPipeSelection.get_global_ptr().make_default_pipe()
+
+    if not pipe.is_valid():
+        pytest.xfail("GraphicsPipe is invalid")
+
+    yield pipe
+
+@pytest.fixture
+def graphics_engine(scope='session'):
+    from panda3d.core import GraphicsEngine
+
+    engine = GraphicsEngine.get_global_ptr()
+    yield engine
+
+@pytest.fixture
+def window(graphics_pipe, graphics_engine):
+    from panda3d.core import GraphicsPipe, FrameBufferProperties, WindowProperties
+
+    fbprops = FrameBufferProperties.get_default()
+    winprops = WindowProperties.get_default()
+
+    win = graphics_engine.make_output(
+        graphics_pipe,
+        'window',
+        0,
+        fbprops,
+        winprops,
+        GraphicsPipe.BF_require_window
+    )
+    graphics_engine.open_windows()
+
+    assert win is not None
+    yield win
+
+    if win is not None:
+        graphics_engine.remove_window(win)

tests/display/test_window.py

@@ -0,0 +1,15 @@
+def test_window_basic(window):
+    from panda3d.core import WindowProperties
+    assert window is not None
+
+    current_props = window.get_properties()
+    default_props = WindowProperties.get_default()
+
+    # Opening the window changes these from the defaults
+    default_props.set_size(current_props.get_size())
+    default_props.set_origin(current_props.get_origin())
+    default_props.set_minimized(False)
+    default_props.set_foreground(True)
+
+    # The rest should be the same
+    assert current_props == default_props