📚 ☔ Add extension docs and tests

Related to moremoban#90

docs/level-12-use-template-engine-extensions/.moban.yml

@@ -0,0 +1,6 @@
+targets:
+  - a.output: a.template
+  - b.output: b.template
+extensions:
+  jinja2:
+    - jinja2.ext.with_

docs/level-12-use-template-engine-extensions/README.rst

@@ -3,16 +3,25 @@ Level 11: use template engine extensions
 
 jinja2 comes with a lot of extensions. In order not to be the blocker in the
 middle, **extensions** is allowed in moban file to initialize jinja2 engine
-with desired extensions
+with desired extensions. Two extensions, expression-statement and loop-controls
+are enabled by default.
 
 The extensions syntax is::
 
    extensions:
      jinja2:
-       - jinja2.ext.do
-	   - jinja2.ext.loopcontrols
+       - jinja2.ext.i18n
 
 
 Evaluation
 --------------------------------------------------------------------------------
+Please go to `docs/level-12-use-template-engine-extensions` directory.
 
+If you notice the file `a.template`, we are using a for loop control. This is
+because moban comes with two default extensions loop-controls and
+expression-statement.
+
+Now, let us try to use the extension `with`. To do that, we have to enable the
+extension in the `.moban.yml` file following the above syntax. Now, the
+extension can be used in the jinja2 templates. One such example is shown in the
+`b.template` file.

docs/level-12-use-template-engine-extensions/a.template

@@ -0,0 +1,3 @@
+{% for _ in range(1,5) %}
+{{ hello }}
+{% endfor %}

docs/level-12-use-template-engine-extensions/b.template

@@ -0,0 +1,9 @@
+{% with %}
+    {% set foo = 142 %}
+{{ foo }}
+    {% with %}
+        {% set foo = 42 %}
+{{ foo }}
+    {% endwith %}
+{{ foo }}
+{% endwith %}

docs/level-12-use-template-engine-extensions/data.yml

@@ -0,0 +1 @@
+hello: world

tests/test_docs.py

@@ -107,6 +107,20 @@ def test_level_11(self):
         folder = "level-11-use-handlebars"
         self._raw_moban(["moban"], folder, expected, "a.output")
 
+    def test_level_12(self):
+        expected_a = """world
+world
+world
+world
+"""
+        expected_b = """142
+42
+142
+"""
+        folder = "level-12-use-template-engine-extensions"
+        self._raw_moban(["moban"], folder, expected_a, "a.output")
+        self._raw_moban(["moban"], folder, expected_b, "b.output")
+
     def test_misc_1(self):
         expected = "test file\n"