Close windows at the end of test functions (#1042)

* Close windows at the end of test functions

* Can't show window deletion warning during interpreter shutdown
starting

pyqtgraph/exporters/tests/test_svg.py

@@ -28,6 +28,7 @@ def test_plotscene():
     ex.export(fileName=tempfilename)
     # clean up after the test is done
     os.unlink(tempfilename)
+    w.close()
 
 def test_simple():
     tempfilename = tempfile.NamedTemporaryFile(suffix='.svg').name

pyqtgraph/graphicsItems/ViewBox/tests/test_ViewBox.py

@@ -71,6 +71,8 @@ def test_ViewBox():
     size1 = QRectF(0, h, w, -h)
     assertMapping(vb, view1, size1)
 
+    win.close()
+
 
 skipreason = "Skipping this test until someone has time to fix it."
 @pytest.mark.skipif(True, reason=skipreason)

pyqtgraph/graphicsItems/tests/test_AxisItem.py

@@ -28,3 +28,5 @@ def test_AxisItem_stopAxisAtTick(monkeypatch):
     monkeypatch.setattr(left, "drawPicture", test_left)
 
     plot.show()
+    app.processEvents()
+    plot.close()

pyqtgraph/graphicsItems/tests/test_ErrorBarItem.py

@@ -35,3 +35,5 @@ def test_ErrorBarItem_defer_data():
     r_clear_ebi = plot.viewRect()
 
     assert r_clear_ebi == r_no_ebi
+
+    plot.close()

pyqtgraph/graphicsItems/tests/test_PlotCurveItem.py

@@ -27,7 +27,8 @@ def test_PlotCurveItem():
     
     c.setData(data, connect=np.array([1,1,1,0,1,1,0,0,1,0,0,0,1,1,0,0]))
     assertImageApproved(p, 'plotcurveitem/connectarray', "Plot curve with connection array.")
-    
+
+    p.close()
 
 
 if __name__ == '__main__':

pyqtgraph/graphicsItems/tests/test_PlotDataItem.py

@@ -86,3 +86,5 @@ def test_clipping():
 
         assert xDisp[0] <= vr.left()
         assert xDisp[-1] >= vr.right()
+
+    w.close()

pyqtgraph/widgets/GraphicsView.py

@@ -411,7 +411,11 @@ class GraphicsView(QtGui.QGraphicsView):
         try:
             if self.parentWidget() is None and self.isVisible():
                 msg = "Visible window deleted. To prevent this, store a reference to the window object."
-                warnings.warn(msg, RuntimeWarning, stacklevel=2)
+                try:
+                    warnings.warn(msg, RuntimeWarning, stacklevel=2)
+                except TypeError:
+                    # warnings module not available during interpreter shutdown
+                    pass
         except RuntimeError:
             pass