Enable debug in run_tests using pdb

When you try to debug some test using nose.tools.set_trace the pdb prompt
is 'trapped' inside tee manipulation of stdout.
    Since debug mode is not supposed to be used in the gates we don't need to
concern about the lack of a log to analyze the output.

Change-Id: I7daebe7267b04d41f2ca383f826419f0dfb544ab

run_tests.sh

@@ -18,6 +18,7 @@ function usage {
   echo "  -c, --coverage           Generate coverage report"
   echo "  -h, --help               Print this usage message"
   echo "  -v, --verbose            Display nosetests in the console"
+  echo "  -d, --debug              Enable pdb's prompt to be displayed during tests. This will run nosetests with --pdb option"
   echo "  --hide-elapsed           Don't print the elapsed time for each test along with slow test list"
   echo ""
   echo "Note: with no options specified, the script will try to run the tests in a virtual environment,"
@@ -40,6 +41,7 @@ function process_option {
     -p|--pep8) just_pep8=1;;
     -P|--no-pep8) no_pep8=1;;
     -c|--coverage) coverage=1;;
+    -d|--debug) debug=1;;
     -v|--verbose) verbose=1;;
     -*) noseopts="$noseopts $1";;
     *) noseargs="$noseargs $1"
@@ -62,6 +64,7 @@ coverage=0
 recreate_db=1
 patch_migrate=1
 verbose=0
+debug=0
 
 export NOSE_WITH_OPENSTACK=1
 export NOSE_OPENSTACK_COLOR=1
@@ -90,6 +93,8 @@ fi
 function run_tests {
   # Cleanup *pyc
   ${wrapper} find . -type f -name "*.pyc" -delete
+  if [ "$debug" -eq 0 ];
+  then
     # Just run the test suites in current environment
     if [ "$verbose" -eq 1 ];
     then
@@ -119,6 +124,10 @@ function run_tests {
           return 1
       fi
     fi
+  else
+    ${wrapper} $NOSETESTS --pdb
+    RESULT=$?
+  fi
   return $RESULT
 }