Merge test-directory-structure test into HTML Proofer's custom checks

Author: yasulab

Rakefile

@@ -3,9 +3,11 @@ task default: 'test'
 # HTML Proofer helps to detect broken links.
 # https://github.com/gjtorikian/html-proofer
 require 'html-proofer'
+require_relative '_tests/custom_checks'
+
 task test: [:build] do
   options = {
-    checks: ['Links', 'Images', 'Scripts', 'OpenGraph', 'Favicon'],
+    checks: ['Links', 'Images', 'Scripts', 'OpenGraph', 'Favicon', 'CustomChecks'],
     allow_hash_href:  false,
     disable_external: true,
     enforce_https:    true,

_tests/custom_checks.rb

@@ -0,0 +1,54 @@
+# See the following 'Custom Tests' section to add tests ;)
+# https://github.com/gjtorikian/html-proofer#custom-tests
+
+require 'json'
+require 'yaml'
+
+class CustomChecks < ::HTMLProofer::Check
+  BASE_PATH = '_site'
+
+  def run
+    current_filename = @runner.current_filename
+    puts "\tchecking ... " + current_filename[5..].split('.').first
+
+    check_directory_structure
+  end
+
+  # Check directory structure to ensure all pages are generated as index.html
+  # This ensures proper routing for both /foobar/ and /foobar pathes.
+  def check_directory_structure
+    allowed_names = ['index.html', '404.html']
+    current_file  = @runner.current_filename
+
+    # Only check HTML files
+    return unless current_file.end_with?('.html')
+
+    # Get the filename
+    filename = File.basename(current_file)
+
+    # Skip if allowed filenames or redirect files
+    return if allowed_names.include?(filename)
+    return if is_redirect_file?(current_file)
+
+    # Report failure for non-index HTML files
+    add_failure(
+      <<~ERROR_MESSAGE
+        index.html でない HTML ファイルが生成されました:
+        \s File: #{current_file}
+        \s すべてのページは index.html として生成される必要があります。
+        \s これにより /path/ と /path の両方でルーティングが可能になります。
+      ERROR_MESSAGE
+    )
+  end
+
+  # Check if it's a redirect or not by meta tags
+  def is_redirect_file?(filepath)
+    return false unless File.exist?(filepath)
+
+    content = File.read(filepath)
+    # Check for meta refresh redirect tag
+    content.include?('<meta http-equiv="refresh"') ||
+    content.include?("<meta http-equiv='refresh'") ||
+    content.include?('<meta http-equiv=refresh')
+  end
+end