use just the page part of the path in breadcrumbs

rather than showing the full path (e.g. /foo/bar/baz) in breadcrumbs
when the page doesn't have a Title, show just the leaf (baz)

Closes #4

tests/test_pages.py

@@ -3,7 +3,7 @@ import pytest
 from werkzeug.http import dump_cookie
 
 from incorporealcms.pages import (generate_parent_navs, instance_resource_path_to_request_path, render,
-                                  request_path_to_instance_resource_path)
+                                  request_path_to_breadcrumb_display, request_path_to_instance_resource_path)
 
 
 def test_generate_page_navs_index(app):
@@ -15,13 +15,13 @@ def test_generate_page_navs_index(app):
 def test_generate_page_navs_subdir_index(app):
     """Test that dir pages have navs to the root and themselves."""
     with app.app_context():
-        assert generate_parent_navs('pages/subdir/index.md') == [('incorporeal.org', '/'), ('/subdir/', '/subdir/')]
+        assert generate_parent_navs('pages/subdir/index.md') == [('incorporeal.org', '/'), ('subdir', '/subdir/')]
 
 
 def test_generate_page_navs_subdir_real_page(app):
     """Test that real pages have navs to the root, their parent, and themselves."""
     with app.app_context():
-        assert generate_parent_navs('pages/subdir/page.md') == [('incorporeal.org', '/'), ('/subdir/', '/subdir/'),
+        assert generate_parent_navs('pages/subdir/page.md') == [('incorporeal.org', '/'), ('subdir', '/subdir/'),
                                                                 ('Page', '/subdir/page')]
 
 
@@ -31,7 +31,7 @@ def test_generate_page_navs_subdir_with_title_parsing_real_page(app):
         assert generate_parent_navs('pages/subdir-with-title/page.md') == [
             ('incorporeal.org', '/'),
             ('SUB!', '/subdir-with-title/'),
-            ('/subdir-with-title/page', '/subdir-with-title/page')
+            ('page', '/subdir-with-title/page')
         ]
 
 
@@ -162,3 +162,12 @@ def test_request_resource_request_page(app):
     """Test that a request can resolve to a resource and back to a request."""
     with app.test_request_context():
         instance_resource_path_to_request_path(request_path_to_instance_resource_path('no-title')) == 'no-title'
+
+
+def test_request_path_to_breadcrumb_display_patterns():
+    """Test various conversions from request path to leaf nodes for display in the breadcrumbs."""
+    assert request_path_to_breadcrumb_display('/foo') == 'foo'
+    assert request_path_to_breadcrumb_display('/foo/') == 'foo'
+    assert request_path_to_breadcrumb_display('/foo/bar') == 'bar'
+    assert request_path_to_breadcrumb_display('/foo/bar/') == 'bar'
+    assert request_path_to_breadcrumb_display('/') == ''