When path arguments are incorrect for RestController, return HTTP 404, not 400.

When RestController encounters a mismatch between function signatures and
positional URL chunks (e.g., /authors/books vs /authors/1/books), it shouldn't
raise an HTTP 400; the issue is a nonexistant URL path, not the structure of
the request/body itself.

Change-Id: I6637f88b7da4f09497f905ebafa7bf1e3788151a

pecan/rest.py

@@ -54,7 +54,10 @@ class RestController(object):
             request.pecan.get('routing_args', [])
         )
         if len(remainder) < fixed_args:
-            abort(400)
+            # For controllers that are missing intermediate IDs
+            # (e.g., /authors/books vs /authors/1/books), return a 404 for an
+            # invalid path.
+            abort(404)
 
     @expose()
     def _route(self, args, request=None):

pecan/tests/test_rest.py

@@ -727,11 +727,11 @@ class TestRestController(PecanTestCase):
         assert r.status_int == 200
         assert r.body == b_('4')
 
-        r = app.get('/foos/bars/', status=400)
-        assert r.status_int == 400
+        r = app.get('/foos/bars/', status=404)
+        assert r.status_int == 404
 
-        r = app.get('/foos/bars/1', status=400)
-        assert r.status_int == 400
+        r = app.get('/foos/bars/1', status=404)
+        assert r.status_int == 404
 
     def test_nested_get_all_with_lookup(self):
 
@@ -783,10 +783,9 @@ class TestRestController(PecanTestCase):
         assert r.status_int == 200
         assert r.body == b_('4')
 
-        r = app.get('/foos/bars/', status=400)
-        assert r.status_int == 400
-
-        r = app.get('/foos/bars/', status=400)
+        r = app.get('/foos/bars/')
+        assert r.status_int == 302
+        assert r.headers['Location'].endswith('/lookup-hit/')
 
         r = app.get('/foos/bars/1')
         assert r.status_int == 302
@@ -893,7 +892,7 @@ class TestRestController(PecanTestCase):
         self.assertEqual(r.body, b_(dumps(dict(items=BarsController.data[1]))))
 
         r = app.get('/foos/bars', expect_errors=True)
-        self.assertEqual(r.status_int, 400)
+        self.assertEqual(r.status_int, 404)
 
     def test_custom_with_trailing_slash(self):