1 files changed, 77 insertions, 0 deletions
diff --git a/spec/ruby/core/hash/merge_spec.rb b/spec/ruby/core/hash/merge_spec.rb
new file mode 100644
index 0000000000..21401ffd08
--- /dev/null
+++ b/spec/ruby/core/hash/merge_spec.rb
@@ -0,0 +1,77 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+require File.expand_path('../shared/iteration', __FILE__)
+require File.expand_path('../shared/update', __FILE__)
+
+describe "Hash#merge" do
+  it "returns a new hash by combining self with the contents of other" do
+    h = { 1 => :a, 2 => :b, 3 => :c }.merge(a: 1, c: 2)
+    h.should == { c: 2, 1 => :a, 2 => :b, a: 1, 3 => :c }
+
+    hash = { a: 1, b: 2 }
+    {}.merge(hash).should == hash
+    hash.merge({}).should == hash
+
+    h = { 1 => :a, 2 => :b, 3 => :c }.merge(1 => :b)
+    h.should == { 1 => :b, 2 => :b, 3 => :c }
+
+    h = { 1 => :a, 2 => :b }.merge(1 => :b, 3 => :c)
+    h.should == { 1 => :b, 2 => :b, 3 => :c }
+  end
+
+  it "sets any duplicate key to the value of block if passed a block" do
+    h1 = { a: 2, b: 1, d: 5 }
+    h2 = { a: -2, b: 4, c: -3 }
+    r = h1.merge(h2) { |k,x,y| nil }
+    r.should == { a: nil, b: nil, c: -3, d: 5 }
+
+    r = h1.merge(h2) { |k,x,y| "#{k}:#{x+2*y}" }
+    r.should == { a: "a:-2", b: "b:9", c: -3, d: 5 }
+
+    lambda {
+      h1.merge(h2) { |k, x, y| raise(IndexError) }
+    }.should raise_error(IndexError)
+
+    r = h1.merge(h1) { |k,x,y| :x }
+    r.should == { a: :x, b: :x, d: :x }
+  end
+
+  it "tries to convert the passed argument to a hash using #to_hash" do
+    obj = mock('{1=>2}')
+    obj.should_receive(:to_hash).and_return({ 1 => 2 })
+    { 3 => 4 }.merge(obj).should == { 1 => 2, 3 => 4 }
+  end
+
+  it "does not call to_hash on hash subclasses" do
+    { 3 => 4 }.merge(HashSpecs::ToHashHash[1 => 2]).should == { 1 => 2, 3 => 4 }
+  end
+
+  it "returns subclass instance for subclasses" do
+    HashSpecs::MyHash[1 => 2, 3 => 4].merge({ 1 => 2 }).should be_an_instance_of(HashSpecs::MyHash)
+    HashSpecs::MyHash[].merge({ 1 => 2 }).should be_an_instance_of(HashSpecs::MyHash)
+
+    { 1 => 2, 3 => 4 }.merge(HashSpecs::MyHash[1 => 2]).class.should == Hash
+    {}.merge(HashSpecs::MyHash[1 => 2]).class.should == Hash
+  end
+
+  it "processes entries with same order as each()" do
+    h = { 1 => 2, 3 => 4, 5 => 6, "x" => nil, nil => 5, [] => [] }
+    merge_pairs = []
+    each_pairs = []
+    h.each_pair { |k, v| each_pairs << [k, v] }
+    h.merge(h) { |k, v1, v2| merge_pairs << [k, v1] }
+    merge_pairs.should == each_pairs
+  end
+
+end
+
+describe "Hash#merge!" do
+  it_behaves_like(:hash_update, :merge!)
+
+  it "does not raise an exception if changing the value of an existing key during iteration" do
+      hash = {1 => 2, 3 => 4, 5 => 6}
+      hash2 = {1 => :foo, 3 => :bar}
+      hash.each { hash.merge!(hash2) }
+      hash.should == {1 => :foo, 3 => :bar, 5 => 6}
+  end
+end