smtbx: remove pytest dependency

- Reverts 0f7535f

smtbx/refinement/constraints/tests/test_direction.py → smtbx/refinement/constraints/tests/tst_direction.py

@@ -1,6 +1,6 @@
 from __future__ import absolute_import, division, print_function
 
-def test_direction():
+def exercise_direction():
   from cctbx.array_family import flex
   from cctbx import uctbx, xray, crystal
   from smtbx.refinement import constraints
@@ -44,3 +44,7 @@ def test_direction():
   nc = row(v01).cross(row(v21)).normalize()
   assert approx_equal(n, n1, eps=1e-15)
   assert approx_equal(n, nc, eps=1e-15)
+
+if __name__ == '__main__':
+  exercise_direction()
+  print('OK')

smtbx/refinement/constraints/tests/test_disorder.py → smtbx/refinement/constraints/tests/tst_disorder.py

@@ -1,7 +1,6 @@
 from __future__ import absolute_import, division, print_function
 
 from six.moves import zip
-
 from six.moves import cStringIO as StringIO
 
 disordered = """
@@ -67,7 +66,7 @@
 HKLF 4
 """
 
-def test_with_disorder():
+def exercise_with_disorder():
   from iotbx import shelx
   from smtbx import refinement
   import smtbx.refinement.constraints as core
@@ -100,3 +99,7 @@ def test_with_disorder():
     assert isinstance(params.site, expected_type)
     assert ([sc1.label for sc1 in params.site.argument(0).scatterers] ==
             [expected_pivot])
+
+if __name__ == '__main__':
+  exercise_with_disorder()
+  print('OK')

smtbx/refinement/constraints/tests/test_occupancies.py → smtbx/refinement/constraints/tests/tst_occupancies.py

@@ -101,7 +101,7 @@
 }
 """
 
-def test_simple_disorder():
+def exercise_simple_disorder():
   ins = fnames.thpp_ins
   model = smtbx.refinement.model.from_shelx(ins)
   ls = model.least_squares()
@@ -113,3 +113,7 @@ def test_simple_disorder():
                       covann.variance_of('C7A.occ'))
   assert approx_equal(covann.variance_of('C3.occ'),
                       covann.variance_of('N3.occ'))
+
+if __name__ == '__main__':
+  exercise_simple_disorder()
+  print('OK')