1 files changed, 68 insertions, 0 deletions
diff --git a/spec/ruby/core/struct/to_h_spec.rb b/spec/ruby/core/struct/to_h_spec.rb
new file mode 100644
index 0000000000..e0846ef268
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+++ b/spec/ruby/core/struct/to_h_spec.rb
@@ -0,0 +1,68 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Struct#to_h" do
+  it "returns a Hash with members as keys" do
+    car = StructClasses::Car.new('Ford', 'Ranger')
+    car.to_h.should == {make: "Ford", model: "Ranger", year: nil}
+  end
+
+  it "returns a Hash that is independent from the struct" do
+    car = StructClasses::Car.new('Ford', 'Ranger')
+    car.to_h[:make] = 'Suzuki'
+    car.make.should == 'Ford'
+  end
+
+  context "with block" do
+    it "converts [key, value] pairs returned by the block to a hash" do
+      car = StructClasses::Car.new('Ford', 'Ranger')
+
+      h = car.to_h { |k, v| [k.to_s, "#{v}".downcase] }
+      h.should == { "make" => "ford", "model" => "ranger", "year" => "" }
+    end
+
+    it "passes to a block each pair's key and value as separate arguments" do
+      s = StructClasses::Ruby.new('3.2.4', 'macos')
+
+      ScratchPad.record []
+      s.to_h { |k, v| ScratchPad << [k, v]; [k, v] }
+      ScratchPad.recorded.sort.should == [[:platform, 'macos'], [:version, '3.2.4']]
+
+      ScratchPad.record []
+      s.to_h { |*args| ScratchPad << args; [args[0], args[1]] }
+      ScratchPad.recorded.sort.should == [[:platform, 'macos'], [:version, '3.2.4']]
+    end
+
+    it "raises ArgumentError if block returns longer or shorter array" do
+      -> do
+        StructClasses::Car.new.to_h { |k, v| [k.to_s, "#{v}".downcase, 1] }
+      end.should.raise(ArgumentError, /element has wrong array length/)
+
+      -> do
+        StructClasses::Car.new.to_h { |k, v| [k] }
+      end.should.raise(ArgumentError, /element has wrong array length/)
+    end
+
+    it "raises TypeError if block returns something other than Array" do
+      -> do
+        StructClasses::Car.new.to_h { |k, v| "not-array" }
+      end.should.raise(TypeError, /wrong element type String/)
+    end
+
+    it "coerces returned pair to Array with #to_ary" do
+      x = mock('x')
+      x.stub!(:to_ary).and_return([:b, 'b'])
+
+      StructClasses::Car.new.to_h { |k| x }.should == { :b => 'b' }
+    end
+
+    it "does not coerce returned pair to Array with #to_a" do
+      x = mock('x')
+      x.stub!(:to_a).and_return([:b, 'b'])
+
+      -> do
+        StructClasses::Car.new.to_h { |k| x }
+      end.should.raise(TypeError, /wrong element type MockObject/)
+    end
+  end
+end