[ruby/prism] Additionally handle encoding comments in vim mode

https://github.com/ruby/prism/commit/bf9bdb9d82

2 files changed, 28 insertions, 1 deletions

diff --git a/test/prism/magic_comment_test.rb b/test/prism/magic_comment_test.rb
index c40364ccfa..76c4fcb71f 100644
--- a/test/prism/magic_comment_test.rb
+++ b/test/prism/magic_comment_test.rb
@@ -16,7 +16,8 @@ module Prism
       "# -*- CoDiNg: ascii -*-",
       "# -*- \s\t\v encoding \s\t\v : \s\t\v ascii \s\t\v -*-",
       "# -*- foo: bar; encoding: ascii -*-",
-      "# coding \t \r  \v   :     \t \v    \r   ascii-8bit\n"
+      "# coding \t \r  \v   :     \t \v    \r   ascii-8bit\n",
+      "# vim: filetype=ruby, fileencoding=big5, tabsize=3, shiftwidth=3\n"
     ]
 
     examples.each do |example|
diff --git a/test/prism/parse_test.rb b/test/prism/parse_test.rb
index aed41b5f84..eada2952df 100644
--- a/test/prism/parse_test.rb
+++ b/test/prism/parse_test.rb
@@ -4,6 +4,21 @@ require_relative "test_helper"
 
 module Prism
   class ParseTest < TestCase
+    # A subclass of Ripper that extracts out magic comments.
+    class MagicCommentRipper < Ripper
+      attr_reader :magic_comments
+
+      def initialize(*)
+        super
+        @magic_comments = []
+      end
+
+      def on_magic_comment(key, value)
+        @magic_comments << [key, value]
+        super
+      end
+    end
+
     # When we pretty-print the trees to compare against the snapshots, we want to
     # be certain that we print with the same external encoding. This is because
     # methods like Symbol#inspect take into account external encoding and it could
@@ -159,6 +174,17 @@ module Prism
           rescue SyntaxError
             raise ArgumentError, "Test file has invalid syntax #{filepath}"
           end
+
+          # Next, check that we get the correct number of magic comments when
+          # lexing with ripper.
+          expected = MagicCommentRipper.new(source).tap(&:parse).magic_comments
+          actual = result.magic_comments
+
+          assert_equal expected.length, actual.length
+          expected.zip(actual).each do |(expected_key, expected_value), magic_comment|
+            assert_equal expected_key, magic_comment.key
+            assert_equal expected_value, magic_comment.value
+          end
         end
       end
     end