Tests: added regex check.

test/unit/check/regex.py

@@ -0,0 +1,13 @@
+import re
+import subprocess
+
+
+def check_regex(unitd):
+    output = subprocess.check_output(
+        [unitd, '--version'], stderr=subprocess.STDOUT
+    )
+
+    if re.search('--no-regex', output.decode()):
+        return False
+
+    return True