Programmatically disable coverage when running on PyPy.

conftest.py

@@ -17,6 +17,24 @@ collect_ignore = [
 ]
 
 
+def pytest_configure(config):
+    disable_coverage_on_pypy(config)
+
+
+def disable_coverage_on_pypy(config):
+    """
+    Coverage makes tests on PyPy unbearably slow, so disable it.
+    """
+    if '__pypy__' not in sys.builtin_module_names:
+        return
+
+    # Recommended at pytest-dev/pytest-cov#418
+    cov = config.pluginmanager.get_plugin('_cov')
+    cov.options.no_cov = True
+    if cov.cov_controller:
+        cov.cov_controller.pause()
+
+
 if sys.version_info < (3,):
     collect_ignore.append('setuptools/lib2to3_ex.py')
     collect_ignore.append('setuptools/_imp.py')

tox.ini

@@ -29,10 +29,6 @@ extras =
 	tests
 
 
-[testenv:pypy{,3}]
-commands = pytest --no-cov {posargs}
-
-
 [testenv:coverage]
 description=Combine coverage data and create report
 deps=coverage