I came up with the following command to do simple syntax check of jinja.
python -c 'from jinja2 import Environment as j; print j().from_string(file("init.sls").read()).render(func=lambda:None)'
Or if you want a simple script:
>>> from jinja2 import Template
>>>
>>> x = '''
... {% for username in 'foo','bar','baz' %}
... {{ username }}:
... user.present:
... - shell: /bin/zsh
... - home: /home/{{ username }}
... {% endfor %}
...
... {% if 'foo' == 'bar' %}
... /tmp/bar:
... file.touch
... {% elif 'foo' == 'foo' %}
... /tmp/foo:
... file.touch
... {% endif %}
... '''
>>> tmpl = Template(x)
>>> print tmpl.render()
Where x is your context / variables.