TST: Skipif decorator for matplotlib #18190

pandas/tests/io/formats/test_style.py

@@ -7,6 +7,7 @@
 import pandas as pd
 from pandas import DataFrame
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 jinja2 = pytest.importorskip('jinja2')
 from pandas.io.formats.style import Styler, _get_level_lengths  # noqa
@@ -1011,8 +1012,8 @@ def test_hide_columns_mult_levels(self):
 
 class TestStylerMatplotlibDep(object):
 
+    @td.skip_if_no_mpl
     def test_background_gradient(self):
-        tm._skip_if_no_mpl()
         df = pd.DataFrame([[1, 2], [2, 4]], columns=['A', 'B'])
 
         for c_map in [None, 'YlOrRd']:

pandas/tests/plotting/common.py

@@ -12,6 +12,7 @@
 import pandas.util.testing as tm
 from pandas.util.testing import (ensure_clean,
                                  assert_is_valid_plot_return_object)
+import pandas.util._test_decorators as td
 
 import numpy as np
 from numpy import random
@@ -23,8 +24,6 @@
 This is a common base class used for various plotting tests
 """
 
-tm._skip_if_no_mpl()
-
 
 def _skip_if_no_scipy_gaussian_kde():
     try:
@@ -43,6 +42,7 @@ def _ok_for_gaussian_kde(kind):
     return plotting._compat._mpl_ge_1_5_0()
 
 
+@td.skip_if_no_mpl
 class TestPlotBase(object):
 
     def setup_method(self, method):

pandas/tests/plotting/test_boxplot_method.py

@@ -8,6 +8,7 @@
 from pandas import Series, DataFrame, MultiIndex
 from pandas.compat import range, lzip
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 import numpy as np
 from numpy import random
@@ -19,8 +20,6 @@
 
 """ Test cases for .boxplot method """
 
-tm._skip_if_no_mpl()
-
 
 def _skip_if_mpl_14_or_dev_boxplot():
     # GH 8382
@@ -31,6 +30,7 @@ def _skip_if_mpl_14_or_dev_boxplot():
         pytest.skip("Matplotlib Regression in 1.4 and current dev.")
 
 
+@td.skip_if_no_mpl
 class TestDataFramePlots(TestPlotBase):
 
     @pytest.mark.slow
@@ -174,6 +174,7 @@ def test_fontsize(self):
                                 xlabelsize=16, ylabelsize=16)
 
 
+@td.skip_if_no_mpl
 class TestDataFrameGroupByPlots(TestPlotBase):
 
     @pytest.mark.slow

pandas/tests/plotting/test_datetimelike.py

@@ -16,13 +16,13 @@
 
 from pandas.util.testing import assert_series_equal, ensure_clean
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 from pandas.tests.plotting.common import (TestPlotBase,
                                           _skip_if_no_scipy_gaussian_kde)
 
-tm._skip_if_no_mpl()
-
 
+@td.skip_if_no_mpl
 class TestTSPlot(TestPlotBase):
 
     def setup_method(self, method):

pandas/tests/plotting/test_deprecated.py

@@ -4,6 +4,7 @@
 
 import pandas as pd
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 import pytest
 
 from numpy.random import randn
@@ -18,9 +19,8 @@
 pandas.tools.plotting
 """
 
-tm._skip_if_no_mpl()
-
 
+@td.skip_if_no_mpl
 class TestDeprecatedNameSpace(TestPlotBase):
 
     @pytest.mark.slow

pandas/tests/plotting/test_frame.py

@@ -15,6 +15,7 @@
 from pandas.compat import range, lrange, lmap, lzip, u, zip, PY3
 from pandas.io.formats.printing import pprint_thing
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 import numpy as np
 from numpy.random import rand, randn
@@ -24,9 +25,8 @@
                                           _skip_if_no_scipy_gaussian_kde,
                                           _ok_for_gaussian_kde)
 
-tm._skip_if_no_mpl()
-
 
+@td.skip_if_no_mpl
 class TestDataFramePlots(TestPlotBase):
 
     def setup_method(self, method):

pandas/tests/plotting/test_groupby.py

@@ -5,14 +5,14 @@
 
 from pandas import Series, DataFrame
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 import numpy as np
 
 from pandas.tests.plotting.common import TestPlotBase
 
-tm._skip_if_no_mpl()
-
 
+@td.skip_if_no_mpl
 class TestDataFrameGroupByPlots(TestPlotBase):
 
     def test_series_groupby_plotting_nominally_works(self):

pandas/tests/plotting/test_hist_method.py

@@ -6,6 +6,7 @@
 
 from pandas import Series, DataFrame
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 import numpy as np
 from numpy.random import randn
@@ -14,9 +15,7 @@
 from pandas.tests.plotting.common import (TestPlotBase, _check_plot_works)
 
 
-tm._skip_if_no_mpl()
-
-
+@td.skip_if_no_mpl
 class TestSeriesPlots(TestPlotBase):
 
     def setup_method(self, method):
@@ -141,6 +140,7 @@ def test_plot_fails_when_ax_differs_from_figure(self):
             self.ts.hist(ax=ax1, figure=fig2)
 
 
+@td.skip_if_no_mpl
 class TestDataFramePlots(TestPlotBase):
 
     @pytest.mark.slow
@@ -251,6 +251,7 @@ def test_tight_layout(self):
             tm.close()
 
 
+@td.skip_if_no_mpl
 class TestDataFrameGroupByPlots(TestPlotBase):
 
     @pytest.mark.slow

pandas/tests/plotting/test_misc.py

@@ -7,6 +7,7 @@
 from pandas import DataFrame
 from pandas.compat import lmap
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 import numpy as np
 from numpy import random
@@ -15,9 +16,8 @@
 import pandas.plotting as plotting
 from pandas.tests.plotting.common import TestPlotBase, _check_plot_works
 
-tm._skip_if_no_mpl()
-
 
+@td.skip_if_no_mpl
 class TestSeriesPlots(TestPlotBase):
 
     def setup_method(self, method):
@@ -49,6 +49,7 @@ def test_bootstrap_plot(self):
         _check_plot_works(bootstrap_plot, series=self.ts, size=10)
 
 
+@td.skip_if_no_mpl
 class TestDataFramePlots(TestPlotBase):
 
     def test_scatter_matrix_axis(self):

pandas/tests/plotting/test_series.py

@@ -12,6 +12,7 @@
 from pandas import Series, DataFrame, date_range
 from pandas.compat import range, lrange
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 
 import numpy as np
 from numpy.random import randn
@@ -21,9 +22,8 @@
                                           _skip_if_no_scipy_gaussian_kde,
                                           _ok_for_gaussian_kde)
 
-tm._skip_if_no_mpl()
-
 
+@td.skip_if_no_mpl
 class TestSeriesPlots(TestPlotBase):
 
     def setup_method(self, method):

pandas/tests/test_resample.py

@@ -13,6 +13,7 @@
 import pandas as pd
 import pandas.tseries.offsets as offsets
 import pandas.util.testing as tm
+import pandas.util._test_decorators as td
 from pandas import (Series, DataFrame, Panel, Index, isna,
                     notna, Timestamp)
 
@@ -234,9 +235,8 @@ def test_groupby_resample_on_api(self):
         result = df.groupby('key').resample('D', on='dates').mean()
         assert_frame_equal(result, expected)
 
+    @td.skip_if_no_mpl
     def test_plot_api(self):
-        tm._skip_if_no_mpl()
-
         # .resample(....).plot(...)
         # hitting warnings
         # GH 12448

pandas/tests/util/test_util.py

@@ -16,6 +16,7 @@
                                      validate_bool_kwarg)
 
 import pandas.util.testing as tm
+from pandas.util._test_decorators import safe_import
 
 
 class TestDecorators(object):
@@ -482,3 +483,20 @@ def test_make_signature():
     assert sig == (['old_arg_name', 'new_arg_name',
                     'mapping=None', 'stacklevel=2'],
                    ['old_arg_name', 'new_arg_name', 'mapping', 'stacklevel'])
+
+
+def test_safe_import(monkeypatch):
+    assert not safe_import("foo")
+    assert not safe_import("pandas", min_version="99.99.99")
+
+    # Create dummy module to be imported
+    import types
+    import sys
+    mod_name = "hello123"
+    mod = types.ModuleType(mod_name)
+    mod.__version__ = "1.5"
+
+    assert not safe_import(mod_name)
+    monkeypatch.setitem(sys.modules, mod_name, mod)
+    assert not safe_import(mod_name, min_version="2.0")
+    assert safe_import(mod_name, min_version="1.0")

pandas/util/_test_decorators.py

@@ -0,0 +1,71 @@
+"""
+This module provides decorator functions which can be applied to test objects
+in order to skip those objects when certain conditions occur. A sample use case
+is to detect if the platform is missing ``matplotlib``. If so, any test objects
+which require ``matplotlib`` and decorated with ``@td.skip_if_no_mpl`` will be
+skipped by ``pytest`` during the execution of the test suite.
+
+To illustrate, after importing this module:
+
+import pandas.util._test_decorators as td
+
+The decorators can be applied to classes:
+
+@td.skip_if_some_reason
+class Foo():
+    ...
+
+Or individual functions:
+
+@td.skip_if_some_reason
+def test_foo():
+    ...
+
+For more information, refer to the ``pytest`` documentation on ``skipif``.
+"""
+
+import pytest
+
+
+def safe_import(mod_name, min_version=None):
+    """
+    Parameters:
+    -----------
+    mod_name : str
+        Name of the module to be imported
+    min_version : str, default None
+        Minimum required version of the specified mod_name
+
+    Returns:
+    --------
+    object
+        The imported module if successful, or False
+    """
+    try:
+        mod = __import__(mod_name)
+    except ImportError:
+        return False
+
+    if not min_version:
+        return mod
+    else:
+        import sys
+        version = getattr(sys.modules[mod_name], '__version__')
+        if version:
+            from distutils.version import LooseVersion
+            if LooseVersion(version) >= LooseVersion(min_version):
+                return mod
+
+    return False
+
+
+def _skip_if_no_mpl():
+    mod = safe_import("matplotlib")
+    if mod:
+        mod.use("Agg", warn=False)
+    else:
+        return True
+
+
+skip_if_no_mpl = pytest.mark.skipif(_skip_if_no_mpl(),
+                                    reason="Missing matplotlib dependency")

pandas/util/testing.py

@@ -325,13 +325,6 @@ def _skip_if_32bit():
         pytest.skip("skipping for 32 bit")
 
 
-def _skip_if_no_mpl():
-    import pytest
-
-    mpl = pytest.importorskip("matplotlib")
-    mpl.use("Agg", warn=False)
-
-
 def _skip_if_mpl_1_5():
     import matplotlib as mpl