Add a new #filter alias for #select

* In Enumerable, Enumerator::Lazy, Array, Hash and Set
  [Feature #13784] [ruby-core:82285]
* Share specs for the various #select#select! methods and
  reuse them for #filter/#filter!.
* Add corresponding filter tests for select tests.
* Update NEWS.

[Fix GH-1824]

From: Alexander Patrick <adp90@case.edu>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62575 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 20 insertions, 0 deletions

diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 955121c0f0..39bf635079 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -170,6 +170,7 @@ class TestArray < Test::Unit::TestCase
   def test_find_all_0
     assert_respond_to([], :find_all)
     assert_respond_to([], :select)       # Alias
+    assert_respond_to([], :filter)       # Alias
     assert_equal([], [].find_all{ |obj| obj == "foo"})
 
     x = ["foo", "bar", "baz", "baz", 1, 2, 3, 3, 4]
@@ -2301,6 +2302,25 @@ class TestArray < Test::Unit::TestCase
     assert_equal(@cls[4, 5], a)
   end
 
+  def test_filter
+    assert_equal([0, 2], [0, 1, 2, 3].filter {|x| x % 2 == 0 })
+  end
+
+  # alias for select!
+  def test_filter!
+    a = @cls[ 1, 2, 3, 4, 5 ]
+    assert_equal(nil, a.filter! { true })
+    assert_equal(@cls[1, 2, 3, 4, 5], a)
+
+    a = @cls[ 1, 2, 3, 4, 5 ]
+    assert_equal(a, a.filter! { false })
+    assert_equal(@cls[], a)
+
+    a = @cls[ 1, 2, 3, 4, 5 ]
+    assert_equal(a, a.filter! { |i| i > 3 })
+    assert_equal(@cls[4, 5], a)
+  end
+
   def test_delete2
     a = [0] * 1024 + [1] + [0] * 1024
     a.delete(0)