Fix incorrect skip check in test_backend_ps.

There was a typo in `elif rcParams.get("ps.userdistiller") == "xpdf"`
which effectively always returned False (the correct spelling is
"ps.usedistiller", so the get() call always returned None), which
made the skip check for xpdf never run.  Thus, running the test on
a machine without pdftops installed would eventually result in an
ExecutableNotFoundError when matplotlib actually tries to call the
distiller.

To avoid this kind of problems (dict.get hiding typos), directly update
the test-specific settings into the main rcParams, and use normal
brackets to access rcParams entries, as rcParams keys are a fixed set
anyways.

Author: anntzer

lib/matplotlib/backends/backend_macosx.py

@@ -147,7 +147,7 @@ def __init__(self, canvas, num):
         icon_path = str(cbook._get_data_path('images/matplotlib.pdf'))
         _macosx.FigureManager.set_icon(icon_path)
         FigureManagerBase.__init__(self, canvas, num)
-        self._set_window_mode(mpl.rcParams.get("macosx.window_mode", "system"))
+        self._set_window_mode(mpl.rcParams["macosx.window_mode"])
         if self.toolbar is not None:
             self.toolbar.update()
         if mpl.is_interactive():

lib/matplotlib/tests/test_backend_ps.py

@@ -40,20 +40,19 @@
     'eps with usetex'
 ])
 def test_savefig_to_stringio(format, use_log, rcParams, orientation, papersize):
-    if rcParams.get("ps.usedistiller") == "ghostscript":
+    mpl.rcParams.update(rcParams)
+    if mpl.rcParams["ps.usedistiller"] == "ghostscript":
         try:
             mpl._get_executable_info("gs")
         except mpl.ExecutableNotFoundError as exc:
             pytest.skip(str(exc))
-    elif rcParams.get("ps.userdistiller") == "xpdf":
+    elif mpl.rcParams["ps.usedistiller"] == "xpdf":
         try:
             mpl._get_executable_info("gs")  # Effectively checks for ps2pdf.
             mpl._get_executable_info("pdftops")
         except mpl.ExecutableNotFoundError as exc:
             pytest.skip(str(exc))
 
-    mpl.rcParams.update(rcParams)
-
     fig, ax = plt.subplots()
 
     with io.StringIO() as s_buf, io.BytesIO() as b_buf:
@@ -67,9 +66,9 @@ def test_savefig_to_stringio(format, use_log, rcParams, orientation, papersize):
             title += " \N{MINUS SIGN}\N{EURO SIGN}"
         ax.set_title(title)
         allowable_exceptions = []
-        if rcParams.get("text.usetex"):
+        if mpl.rcParams["text.usetex"]:
             allowable_exceptions.append(RuntimeError)
-        if rcParams.get("ps.useafm"):
+        if mpl.rcParams["ps.useafm"]:
             allowable_exceptions.append(mpl.MatplotlibDeprecationWarning)
         try:
             fig.savefig(s_buf, format=format, orientation=orientation,
@@ -87,14 +86,14 @@ def test_savefig_to_stringio(format, use_log, rcParams, orientation, papersize):
         if format == 'ps':
             # Default figsize = (8, 6) inches = (576, 432) points = (203.2, 152.4) mm.
             # Landscape orientation will swap dimensions.
-            if rcParams.get("ps.usedistiller") == "xpdf":
+            if mpl.rcParams["ps.usedistiller"] == "xpdf":
                 # Some versions specifically show letter/203x152, but not all,
                 # so we can only use this simpler test.
                 if papersize == 'figure':
                     assert b'letter' not in s_val.lower()
                 else:
                     assert b'letter' in s_val.lower()
-            elif rcParams.get("ps.usedistiller") or rcParams.get("text.usetex"):
+            elif mpl.rcParams["ps.usedistiller"] or mpl.rcParams["text.usetex"]:
                 width = b'432.0' if orientation == 'landscape' else b'576.0'
                 wanted = (b'-dDEVICEWIDTHPOINTS=' + width if papersize == 'figure'
                           else b'-sPAPERSIZE')