test(tox): Add cython envs to tox and travis

In order to catch any subtle cython errors, this patch ensures we are
gating on some cython envs.

.travis.yml

@@ -3,7 +3,9 @@ install: pip install tox coveralls --use-mirrors
 env:
   - TOX_ENV=py26
   - TOX_ENV=py27
+  - TOX_ENV=py27_cython
   - TOX_ENV=py33
+  - TOX_ENV=py33_cython
   - TOX_ENV=pep8
   - TOX_ENV=pylint
 

falcon/bench/bench.py

@@ -42,7 +42,7 @@ def bench(name, iterations, env, stat_memory):
     if heapy and stat_memory:
         heap_diff = heapy.heap() - heap_before
 
-    sec_per_req = Decimal(total_sec) / Decimal(iterations)
+    sec_per_req = Decimal(str(total_sec)) / Decimal(str(iterations))
 
     sys.stdout.write('.')
     sys.stdout.flush()

tox.ini

@@ -1,5 +1,16 @@
 [tox]
-envlist = py26,py27,py33,pypy,pep8,pylint,py26_bench,py27_bench,py33_bench,pypy_bench
+envlist = py26,
+          py27,
+          py27_cython,
+          py33,
+          py33_cython,
+          pypy,
+          pep8,
+          pylint,
+          py26_bench,
+          py27_bench,
+          py33_bench,
+          pypy_bench
 
 [testenv]
 deps = -r{toxinidir}/tools/test-requires
@@ -16,6 +27,22 @@ commands = {toxinidir}/tools/clean_cythoned.sh {toxinidir}/falcon
                --cprofile-stats-file=cprofile.dat \
                {posargs}
 
+[testenv:py27_cython]
+deps = -r{toxinidir}/tools/test-requires
+       cython
+basepython = python2.7
+commands = {toxinidir}/tools/clean_cythoned.sh {toxinidir}/falcon
+           nosetests \
+               {posargs}
+
+[testenv:py33_cython]
+deps = -r{toxinidir}/tools/test-requires
+       cython
+basepython = python3.3
+commands = {toxinidir}/tools/clean_cythoned.sh {toxinidir}/falcon
+           nosetests \
+               {posargs}
+
 [testenv:py3kwarn]
 deps = py3kwarn
 commands = py3kwarn falcon