Remove Cython-based tests (#1793)

The Cython tests have long outlived their usefulness, and represent a
maintainability risk. This PR removes them.

Closes #845.

.github/workflows/test-from-pypi.yml

@@ -48,11 +48,11 @@ jobs:
         allow-prereleases: true
     - name: Install test dependencies and Traits from PyPI sdist (no PySide6)
       run: |
-        python -m pip install --no-binary traits Cython numpy setuptools Sphinx traits traitsui
+        python -m pip install --no-binary traits numpy setuptools Sphinx traits traitsui
       if: matrix.python-version == '3.12' || matrix.python-architecture == 'x86'
     - name: Install test dependencies and Traits from PyPI sdist (PySide6)
       run: |
-        python -m pip install --no-binary traits Cython numpy PySide6 setuptools Sphinx traits traitsui
+        python -m pip install --no-binary traits numpy PySide6 setuptools Sphinx traits traitsui
       if: matrix.python-version != '3.12' && matrix.python-architecture != 'x86'
     - name: Create clean test directory
       run: |
@@ -100,11 +100,11 @@ jobs:
         allow-prereleases: true
     - name: Install test dependencies and Traits from PyPI wheel (no PySide6)
       run: |
-        python -m pip install --only-binary traits Cython numpy setuptools Sphinx traits traitsui
+        python -m pip install --only-binary traits numpy setuptools Sphinx traits traitsui
       if: matrix.python-version == '3.12' || matrix.python-architecture == 'x86'
     - name: Install test dependencies and Traits from PyPI wheel (PySide6)
       run: |
-        python -m pip install --only-binary traits Cython numpy PySide6 setuptools Sphinx traits traitsui
+        python -m pip install --only-binary traits numpy PySide6 setuptools Sphinx traits traitsui
       if: matrix.python-version != '3.12' && matrix.python-architecture != 'x86'
     - name: Create clean test directory
       run: |

etstool.py

@@ -89,7 +89,6 @@
 common_dependencies = {
     "configobj",
     "coverage",
-    "cython",
     "enthought_sphinx_theme",
     "flake8",
     "flake8_ets",

setup.py

@@ -301,7 +301,6 @@ def get_long_description():
             "sphinx-copybutton",
         ],
         "test": [
-            "Cython",
             # defusedxml is required by the Sphinx test machinery
             # for recent versions of Sphinx (including 7.3.7)
             "defusedxml",

traits/has_traits.py

@@ -184,7 +184,7 @@ def is_unbound_method_type(method):
     and _name_fired methods.
 
     """
-    # The ismethoddescriptor check catches methods written in C or Cython
+    # The ismethoddescriptor check catches methods written in C
     # extensions. It excludes things that pass an isfunction check, so we have
     # to explicitly re-include that check.
     return inspect.isfunction(method) or inspect.ismethoddescriptor(method)

traits/testing/optional_dependencies.py

@@ -36,9 +36,6 @@ def optional_import(name):
 
 
 # Commonly-used unittest skip decorators.
-cython = optional_import("cython")
-requires_cython = unittest.skipIf(cython is None, "Cython not available")
-
 mypy = optional_import("mypy")
 requires_mypy = unittest.skipIf(mypy is None, "Mypy not available")