Fix documentation reg. unittest, add run_tests.py

There is a problem with running nosetest - the previous html coverage reports
are not properly removed thus subsequent runs of nosetest --with-coverage...
result in "File exists error".

The old run_tests.py file was restored and put into the main directory. It takes
care of removing old html reports and running the tests.

.coveragerc

@@ -0,0 +1,26 @@
+# .coveragerc to control coverage.py
+[run]
+branch = True
+exclude_lines =
+    # Have to re-enable the standard pragma
+    pragma: no cover
+
+    # Don't complain about missing debug-only code:
+    def __repr__
+    if self\.debug
+
+    # Don't complain if tests don't hit defensive assertion code:
+    raise AssertionError
+    raise NotImplementedError
+
+    # Don't complain if non-runnable code isn't run:
+    if 0:
+    if __name__ == .__main__.:
+source =
+    ./certcheck/
+
+
+[html]
+directory = test/output_coverage_html
+
+[paths]

README.md

@@ -140,13 +140,43 @@ test/ directory you can find:
 - moduletests/ - the unittests themselves
 - fabric/ - sample input files and test certificates temporary directories
 - output_coverage_html/ - coverage tests results in a form of an html webpage
-- test.py - script to start all the unittests
+
+Unittests can be started either by using *nosetest* command:
+
+```
+certcheck/ (master✗) # nosetests
+[20:33:02]
+......
+----------------------------------------------------------------------
+Ran 6 tests in 0.449s
+
+OK
+```
+
+or by issuing the *run_tests.py* command:
+
+```
+certcheck/ (master✗) # run_tests.py
+[20:33:04]
+Created test certificate expired_3_days.pem
+Created test certificate expire_6_days.pem
+Created test certificate expire_21_days.pem
+Created test certificate expire_41_days.pem
+Created test certificate expire_41_days.der
+......
+----------------------------------------------------------------------
+Ran 6 tests in 0.362s
+
+OK
+```
+
+The difference is that the *run_tests.py* takes care of generating coverage
+reports for you.
 
 All the dependencies required for performing the unittests are decribed in debian
 packaging scripts and are as follows:
 - unittests2
 - coverage
 - python-mock
 - openssl command in the PATH
-
-Plus all the dependencies mentioned in 'Project Setup' section.
+, plus all the dependencies mentioned in 'Project Setup' section.

run_tests.py

@@ -0,0 +1,48 @@
+#!/usr/bin/python -tt
+
+#Make it a bit more like python3:
+from __future__ import absolute_import
+from __future__ import print_function
+
+import coverage
+import os
+import shutil
+import sys
+import unittest
+
+
+def main():
+    major, minor, micro, releaselevel, serial = sys.version_info
+
+    if major == 2 and minor < 7:
+        print("In order to run tests you need at least Python 2.7")
+        sys.exit(1)
+
+    if major == 3:
+        print("Tests were not tested on Python 3.X, use at your own risk")
+        sys.exit(1)
+
+    #Cleanup old html report:
+    for root, dirs, files in os.walk('test/output_coverage_html/'):
+        for f in files:
+            if f == '.gitignore' or f == '.empty_dir':
+                continue
+            os.unlink(os.path.join(root, f))
+        for d in dirs:
+            shutil.rmtree(os.path.join(root, d))
+
+    #Perform coverage analisys:
+    cov = coverage.coverage()
+
+    cov.start()
+    #Discover the test and execute them:
+    loader = unittest.TestLoader()
+    tests = loader.discover('./test/')
+    testRunner = unittest.runner.TextTestRunner(descriptions=True, verbosity=1)
+    testRunner.run(tests)
+    cov.stop()
+
+    cov.html_report()
+
+if __name__ == '__main__':
+    main()