return correct file in dir if dir has same name as file (#6569)

Merge pull request 6569

test/fixtures/webrick/bar.html

@@ -0,0 +1 @@
+Content of bar.html

test/fixtures/webrick/bar/baz.html

@@ -0,0 +1 @@
+Content of baz.html

test/helper.rb

@@ -44,6 +44,8 @@ require "shoulda"
 
 include Jekyll
 
+require "jekyll/commands/serve/servlet"
+
 # Report with color.
 Minitest::Reporters.use! [
   Minitest::Reporters::DefaultReporter.new(
@@ -194,3 +196,55 @@ class JekyllUnitTest < Minitest::Test
     end
   end
 end
+
+class FakeLogger
+  def <<(str); end
+end
+
+module TestWEBrick
+
+  module_function
+
+  def mount_server(&block)
+    server = WEBrick::HTTPServer.new(config)
+
+    begin
+      server.mount("/", Jekyll::Commands::Serve::Servlet, document_root,
+        document_root_options)
+
+      server.start
+      addr = server.listeners[0].addr
+      block.yield([server, addr[3], addr[1]])
+    rescue StandardError => e
+      raise e
+    ensure
+      server.shutdown
+      sleep 0.1 until server.status == :Stop
+    end
+  end
+
+  def config
+    logger = FakeLogger.new
+    {
+      :BindAddress => "127.0.0.1", :Port => 0,
+      :ShutdownSocketWithoutClose => true,
+      :ServerType => Thread,
+      :Logger => WEBrick::Log.new(logger),
+      :AccessLog => [[logger, ""]],
+      :JekyllOptions => {},
+    }
+  end
+
+  def document_root
+    "#{File.dirname(__FILE__)}/fixtures/webrick"
+  end
+
+  def document_root_options
+    WEBrick::Config::FileHandler.merge({
+      :FancyIndexing     => true,
+      :NondisclosureName => [
+        ".ht*", "~*",
+      ],
+    })
+  end
+end

test/test_commands_serve_servlet.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "webrick"
+require "helper"
+require "net/http"
+
+class TestCommandsServeServlet < JekyllUnitTest
+  def get(path)
+    TestWEBrick.mount_server do |_server, addr, port|
+      http = Net::HTTP.new(addr, port)
+      req = Net::HTTP::Get.new(path)
+
+      http.request(req) { |response| yield(response) }
+    end
+  end
+
+  context "with a directory and file with the same name" do
+    should "find that file" do
+      get("/bar/") do |response|
+        assert_equal("200", response.code)
+        assert_equal("Content of bar.html", response.body.strip)
+      end
+    end
+
+    should "find file in directory" do
+      get("/bar/baz") do |response|
+        assert_equal("200", response.code)
+        assert_equal("Content of baz.html", response.body.strip)
+      end
+    end
+
+    should "return 404 for non-existing files" do
+      get("/bar/missing") do |response|
+        assert_equal("404", response.code)
+      end
+    end
+  end
+end