diff -r abc83875167e -r 4da025d0b283 tests/misc.py
--- a/tests/misc.py	Fri May 24 17:44:04 2019 +0200
+++ b/tests/misc.py	Sat May 25 09:41:33 2019 +0200
@@ -16,10 +16,20 @@
         if isinstance(element, linetypes.Error)
     )
 
+def bad_header(model):
+    import header
+    if isinstance(model.header, header.BadHeader):
+        yield error(
+            model.body[model.header.index],
+            'bad-header',
+            reason = model.header.reason,
+        )
+
 manifest = {
     'tests': {
         'colour-validity': colours_test,
         'syntax-errors': syntax_errors,
+        'header-validity': bad_header,
     },
     'messages': {
         'bad-colour': lambda colour_index: str.format(
@@ -30,5 +40,9 @@
             'syntax error: {}',
             reason,
         ),
+        'bad-header': lambda reason: str.format(
+            'bad header: {}',
+            reason,
+        ),
     },
 }