ENH: completion can use different todo.sh locations and configurations.

This was previously not supported; todo_completion always used plain todo.sh from the PATH. Now it's possible to override the used executable (and configuration used through _todo_sh, set from a completion function wrapper.

Cp. http://tech.groups.yahoo.com/group/todotxt/message/4003

tests/t6090-completion-aliases.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+#
+
+test_description='Bash completion with different aliases functionality
+
+This test checks that todo_completion can use a different configuration
+when another todo.sh alias is defined that uses that configuration.
+'
+. ./test-lib.sh
+
+cat > todo.txt <<EOF
+(B) smell the +roses @outside @outdoor +shared
+notice the sunflowers +sunflowers @outside @garden +shared +landscape
+stop
+EOF
+cat > todo2.txt <<EOF
++herbs @oriental buy spices
++slack @home watch tv
+EOF
+
+cp todo.cfg todo2.cfg
+cat >> todo2.cfg <<'EOF'
+export TODO_FILE="$TODO_DIR/todo2.txt"
+EOF
+
+# Note: We cannot use aliases within the test framework, but functions are
+# equivalent and work fine.
+todo1()
+{
+    todo.sh "$@"
+}
+todo2()
+{
+    todo.sh -d "$HOME/todo2.cfg" "$@"
+}
+
+# Ensure that the test fixture works as planned.
+test_todo_session 'todo 1 and 2 contexts' <<EOF
+>>> todo1 listcon
+@garden
+@outdoor
+@outside
+
+>>> todo2 listcon
+@home
+@oriental
+EOF
+
+
+# Define a second completion function that injects the different configuration
+# file. In real use, this would be installed via
+#   complete -F _todo2 todo2
+_todo2()
+{
+    local _todo_sh='todo.sh -d "$HOME/todo2.cfg"'
+    _todo "$@"
+}
+
+test_todo_completion               'all todo1 contexts' 'todo1 list @' '@garden @outdoor @outside'
+test_todo_custom_completion _todo2 'all todo2 contexts' 'todo2 list @' '@home @oriental'
+
+test_done