Having issues in Unit TestCases for Custom Loader for template in django

I wrote a custom loader in django which is performing some 'regular expression' changes in template and In unit testcase for the loader I want to check the changes in the template. But django loader didn't returns any template_string attribute with template object.

For Example

I am removing new line i.e. '\n' after every '%}' in the template with the help of custom loader by performing re operations over it.

Now I need to check this after loader performs re operations over template in the TestCases.

template:

{% for i in list %}\n
{{ i }}
{% endfor %}\n

in Unit Test Case:

template = loader.get_template("path/to/template")

#How I can retrieve template_string from template object? 
#to put in place of 'output'

self.assertEqual(output ,"{% for i in list%}{{ i }}{% endfor %}")

The expected output I need to match is {% for i in list%}{{ i }}{% endfor %}. How can I get the template_string from the template object?