add instrumental to tox config

Author: tomato42

tox.ini

@@ -55,6 +55,19 @@ basepython=python2.7
 [testenv:gmpy2py39]
 basepython=python3.9
 
+[testenv:instrumental]
+basepython = python2.7
+deps =
+     gmpy2
+     instrumental
+     hypothesis
+     pytest>=4.6.0
+     coverage==4.5.4
+     six
+commands =
+         instrumental -t ecdsa -i 'test.*|.*_version|.*_compat' {envbindir}/pytest {posargs:src/ecdsa}
+         instrumental -f .instrumental.cov -sr
+
 [testenv:coverage]
 sitepackages=True
 whitelist_externals=coverage