Add test: show() closes figures when matplotlib has no pyplot attribute (#24)

Author: Chris

tests/test_import.py

@@ -2,3 +2,17 @@ def test_import():
     from matplotlib_inline.backend_inline import show
 
     show()
+
+
+def test_show_closes_figures_without_pyplot_attribute(monkeypatch):
+    # gh-24: lazy loaders (e.g. librosa < 0.10.1) can leave matplotlib.pyplot
+    # in sys.modules without setting it as an attribute of matplotlib.
+    import matplotlib
+    import matplotlib.pyplot as plt
+
+    from matplotlib_inline.backend_inline import show
+
+    plt.figure()
+    monkeypatch.delattr(matplotlib, "pyplot")
+    show(close=True)
+    assert plt.get_fignums() == []