tests: check that a jinja2 error reports which file fails to render

slapos/recipe/template/README.jinja2.txt

@@ -514,6 +514,34 @@ Let's just use ``buildout.cfg`` using this egg::
     >>> cat('foo')
     foobar
 
+Errors in template
+~~~~~~~~~~~~~~~~~~
+
+    >>> write('template.in', '''\
+    ... foo
+    ... {%
+    ... bar
+    ... ''')
+    >>> write('buildout.cfg', '''
+    ... [buildout]
+    ... parts = template
+    ...
+    ... [template]
+    ... recipe = slapos.recipe.template:jinja2
+    ... template = template.in
+    ... rendered = foo
+    ... ''')
+    >>> 0; run_buildout() # doctest: +ELLIPSIS
+    0...
+    While:
+      Installing template.
+    ...
+    Traceback (most recent call last):
+      ...
+      File "template.in", line 3, in template
+        bar
+    ...TemplateSyntaxError: Encountered unknown tag 'bar'.
+
 Avoiding file re-creation
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -535,16 +563,9 @@ rendering.
     ... rendered = foo_once
     ... once = foo_flag
     ... ''')
-    >>> run_buildout() # doctest: +ELLIPSIS
-    Uninstalling template.
-    Uninstalling sample.
-    Getting distribution for 'samplerecipe'.
-    Got samplerecipe 0.0.0.
+    >>> run_buildout()
     Installing template.
     The template install returned None.  A path or iterable os paths should be returned.
-    warning: install_lib: '...' does not exist -- no Python modules to install
-    <BLANKLINE>
-    zip_safe flag not set; analyzing archive contents...
 
 Template was rendered::