Add failing test for permalink templates with trailing underscores

test/helper.rb

@@ -103,6 +103,21 @@ class JekyllUnitTest < Minitest::Test
     RSpec::Mocks.teardown
   end
 
+  def fixture_document(relative_path)
+    site = fixture_site({
+      "collections" => {
+        "methods" => {
+          "output" => true
+        }
+      }
+    })
+    site.read
+    matching_doc = site.collections["methods"].docs.find do |doc|
+      doc.relative_path == relative_path
+    end
+    [site, matching_doc]
+  end
+
   def fixture_site(overrides = {})
     Jekyll::Site.new(site_configuration(overrides))
   end

test/test_url.rb

@@ -54,17 +54,7 @@ class TestURL < JekyllUnitTest
     end
 
     should "handle UrlDrop as a placeholder in addition to a hash" do
-      site = fixture_site({
-        "collections" => {
-          "methods" => {
-            "output" => true
-          }
-        }
-      })
-      site.read
-      matching_doc = site.collections["methods"].docs.find do |doc|
-        doc.relative_path == "_methods/escape-+ #%20[].md"
-      end
+      _, matching_doc = fixture_document("_methods/escape-+ #%20[].md")
       assert_equal "/methods/escape-+-20/escape-20.html", URL.new(
         :template     => "/methods/:title/:name:output_ext",
         :placeholders => matching_doc.url_placeholders
@@ -81,18 +71,16 @@ class TestURL < JekyllUnitTest
       end
     end
 
-    should "ignore NoMethodErrors when a placeholder is not found" do
-      site = fixture_site({
-        "collections" => {
-          "methods" => {
-            "output" => true
-          }
-        }
-      })
-      site.read
-      matching_doc = site.collections["methods"].docs.find do |doc|
-        doc.relative_path == "_methods/escape-+ #%20[].md"
+    should "check for key without trailing underscore" do
+      _, matching_doc = fixture_document("_methods/configuration.md")
+      assert_equal "/lol", URL.new(
+        :template => "/:year-:month-:day_:title",
+        :placeholders => matching_doc.url_placeholders
+      ).to_s
     end
+
+    should "raise custom error when URL placeholder doesn't have key" do
+      _, matching_doc = fixture_document("_methods/escape-+ #%20[].md")
       assert_raises NoMethodError do
         URL.new(
           :template     => "/methods/:headline",