Add a Ripper.lex test of :on_embexpr_end

This is a weird use case of Ripper.lex which I'm not sure is supposed to
be maintained, so I'm adding this test so that we can easily notice such
changes.

If we change the behavior, this will break the behavior of hamlit.gem v1
and code like https://github.com/haml/haml/pull/1043.

1 files changed, 7 insertions, 0 deletions

diff --git a/test/ripper/test_lexer.rb b/test/ripper/test_lexer.rb
index 1794773d89..3fc44234b9 100644
--- a/test/ripper/test_lexer.rb
+++ b/test/ripper/test_lexer.rb
@@ -138,4 +138,11 @@ class TestRipper::Lexer < Test::Unit::TestCase
     assert_equal pos, code.bytesize
     assert_equal expected.size, result.size
   end
+
+  def test_trailing_on_embexpr_end
+    # This is useful for scanning a template engine literal `{ foo, bar: baz }`
+    # whose body inside brackes works like trailing method arguments, like Haml.
+    token = Ripper.lex("a( foo, bar: baz }").last
+    assert_equal [[1, 17], :on_embexpr_end, "}", state(:EXPR_ARG)], token
+  end
 end