do an actual test run

tests/base.py

@@ -0,0 +1,54 @@
+# pylint: disable=unused-import
+
+from os.path import dirname, realpath
+from os import chdir
+import sys
+import logging
+import io
+import collections
+from unittest import TestCase as VanillaTestCase, skip, main as unittests_main
+import pytest
+from ocrd_utils import disableLogging, initLogging
+
+def main(fn=None):
+    if fn:
+        sys.exit(pytest.main([fn]))
+    else:
+        unittests_main()
+
+class TestCase(VanillaTestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        chdir(dirname(realpath(__file__)) + '/..')
+
+    def setUp(self):
+        disableLogging()
+        initLogging()
+
+class CapturingTestCase(TestCase):
+    """
+    A TestCase that needs to capture stderr/stdout and invoke click CLI.
+    """
+
+    @pytest.fixture(autouse=True)
+    def _setup_pytest_capfd(self, capfd):
+        self.capfd = capfd
+
+    def invoke_cli(self, cli, args):
+        """
+        Substitution for click.CliRunner.invooke that works together nicely
+        with unittests/pytest capturing stdout/stderr.
+        """
+        self.capture_out_err()  # XXX snapshot just before executing the CLI
+        code = 0
+        sys.argv[1:] = args # XXX necessary because sys.argv reflects pytest args not cli args
+        try:
+            cli.main(args=args)
+        except SystemExit as e:
+            code = e.code
+        out, err = self.capture_out_err()
+        return code, out, err
+
+    def capture_out_err(self):
+        return self.capfd.readouterr()