Added doc_plex (#35)

* added test file with assert

* Fixed problem.

* Updated to correct:

tests/test_docplex.py:4:1: E302 expected 2 blank lines, found 1
tests/test_docplex.py:10:12: E714 test for object identity should be 'is not'
tests/test_docplex.py:10:27: W292 no newline at end of file

* another improvement

* update

setup.py

@@ -36,7 +36,10 @@
       install_requires=['cython', 'pyriemann @ git+https://github.com/pyRiemann/pyRiemann#egg=pyriemann',
                         'qiskit==0.20.0', 'cvxpy==1.1.12',
                         'scipy==1.5.4; python_version < "3.7.0"',
-                        'scipy==1.7.3; python_version >= "3.7.0"'],
+                        'scipy==1.7.3; python_version >= "3.7.0"',
+                        'docplex',
+                        'tqdm'
+                        ],
       extras_require={'docs': ['sphinx-gallery', 'sphinx-bootstrap_theme', 'numpydoc', 'mne', 'seaborn'],
                       'tests': ['pytest', 'seaborn', 'flake8', 'mne', 'pooch', 'tqdm']},
       zip_safe=False,

tests/test_docplex.py

@@ -0,0 +1,11 @@
+from docplex.mp.vartype import ContinuousVarType
+from docplex.mp.model import Model
+
+
+def test_get_square_cont_var():
+    channels = range(4)
+    prob = Model()
+    ContinuousVarType.one_letter_symbol = lambda _: 'C'
+    mat = prob.continuous_var_matrix(keys1=channels, keys2=channels,
+                                     name='test', lb=-prob.infinity)
+    assert mat is not None