Fix Enumerator#each_with_index with block

In previous version,

```
a = [3, 2, 1]
e = a.each
e.sort_by(&:to_i) # => []
```

In this version,

```
a = [3, 2, 1]
e = a.each
e.sort_by(&:to_i) # => [1, 2, 3]
```

1 files changed, 7 insertions, 0 deletions

diff --git a/mrbgems/mruby-enumerator/test/enumerator.rb b/mrbgems/mruby-enumerator/test/enumerator.rb
index e86e874f0..763cd36e2 100644
--- a/mrbgems/mruby-enumerator/test/enumerator.rb
+++ b/mrbgems/mruby-enumerator/test/enumerator.rb
@@ -65,6 +65,13 @@ assert 'Enumerator#with_index string offset' do
   assert_raise(TypeError){ @obj.to_enum(:foo, 1, 2, 3).with_index('1').to_a }
 end
 
+assert 'Enumerator#each_with_index' do
+  assert_equal([[1,0],[2,1],[3,2]], @obj.to_enum(:foo, 1, 2, 3).each_with_index.to_a)
+  a = []
+  @obj.to_enum(:foo, 1, 2, 3).each_with_index {|*i| a << i}
+  assert_equal([[1, 0], [2, 1], [3, 2]], a)
+end
+
 assert 'Enumerator#with_object' do
   obj = [0, 1]
   ret = (1..10).each.with_object(obj) {|i, memo|