Support "workon ."

If the literal string "." is passed to workon, use the current working
directory to derive the virtualenv name. Activation happens normally,
which may involve changing directories out of the current directory
(possibly even changing back, depending on what postactivate hooks do).

Change-Id: Ia2de0bf05a52a95e4979c58bd868ae309f23540d

Author: dhellmann

tests/test_workon.sh

@@ -116,4 +116,11 @@ test_no_workon_home () {
     WORKON_HOME="$old_home"
 }
 
+test_workon_dot () {
+    cd $WORKON_HOME/env1
+    workon .
+    assertTrue virtualenvwrapper_verify_active_environment
+    assertSame "env1" $(basename "$VIRTUAL_ENV")
+}
+
 . "$test_dir/shunit2"

virtualenvwrapper.sh

@@ -722,6 +722,9 @@ function workon {
     then
         lsvirtualenv -b
         return 1
+    elif [ "$env_name" = "." ]
+    then
+        env_name=$(basename $(pwd))
     fi
 
     virtualenvwrapper_verify_workon_home || return 1