1 files changed, 37 insertions, 0 deletions
diff --git a/spec/ruby/core/enumerable/group_by_spec.rb b/spec/ruby/core/enumerable/group_by_spec.rb
new file mode 100644
index 0000000000..904e5d6c68
--- /dev/null
+++ b/spec/ruby/core/enumerable/group_by_spec.rb
@@ -0,0 +1,37 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+require_relative 'shared/enumerable_enumeratorized'
+
+describe "Enumerable#group_by" do
+  it "returns a hash with values grouped according to the block" do
+    e = EnumerableSpecs::Numerous.new("foo", "bar", "baz")
+    h = e.group_by { |word| word[0..0].to_sym }
+    h.should == { f: ["foo"], b: ["bar", "baz"]}
+  end
+
+  it "returns an empty hash for empty enumerables" do
+    EnumerableSpecs::Empty.new.group_by { |x| x}.should == {}
+  end
+
+  it "returns a hash without default_proc" do
+    e = EnumerableSpecs::Numerous.new("foo", "bar", "baz")
+    h = e.group_by { |word| word[0..0].to_sym }
+    h[:some].should == nil
+    h.default_proc.should == nil
+    h.default.should == nil
+  end
+
+  it "returns an Enumerator if called without a block" do
+    EnumerableSpecs::Numerous.new.group_by.should.instance_of?(Enumerator)
+  end
+
+  it "gathers whole arrays as elements when each yields multiple" do
+    e = EnumerableSpecs::YieldsMulti.new
+    h = e.group_by { |i| i }
+    h.should == { [1, 2] => [[1, 2]],
+                  [6, 7, 8, 9] => [[6, 7, 8, 9]],
+                  [3, 4, 5] => [[3, 4, 5]] }
+  end
+
+  it_behaves_like :enumerable_enumeratorized_with_origin_size, :group_by
+end