diff --git a/spec/core/data/to_h_spec.rb b/spec/core/data/to_h_spec.rb
new file mode 100644
index 000000000..41d6960c9
--- /dev/null
+++ b/spec/core/data/to_h_spec.rb
@@ -0,0 +1,65 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+ruby_version_is "3.2" do
+  describe "Data#to_h" do
+    it "transforms the data object into a hash" do
+      data = DataSpecs::Measure.new(amount: 42, unit: 'km')
+      data.to_h.should == { amount: 42, unit: 'km' }
+    end
+
+    context "with block" do
+      it "transforms [key, value] pairs returned by the block into a hash" do
+        data = DataSpecs::Measure.new(amount: 42, unit: 'km')
+        data.to_h { |key, value| [value, key] }.should == { 42 => :amount, 'km' => :unit }
+      end
+
+      it "passes to a block each pair's key and value as separate arguments" do
+        ScratchPad.record []
+        data = DataSpecs::Measure.new(amount: 42, unit: 'km')
+        data.to_h { |k, v| ScratchPad << [k, v]; [k, v] }
+        ScratchPad.recorded.sort.should == [[:amount, 42], [:unit, 'km']]
+
+        ScratchPad.record []
+        data.to_h { |*args| ScratchPad << args; [args[0], args[1]] }
+        ScratchPad.recorded.sort.should == [[:amount, 42], [:unit, 'km']]
+      end
+
+      it "raises ArgumentError if block returns longer or shorter array" do
+        data = DataSpecs::Measure.new(amount: 42, unit: 'km')
+        -> do
+          data.to_h { |k, v| [k.to_s, v*v, 1] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+
+        -> do
+          data.to_h { |k, v| [k] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+      end
+
+      it "raises TypeError if block returns something other than Array" do
+        data = DataSpecs::Measure.new(amount: 42, unit: 'km')
+        -> do
+          data.to_h { |k, v| "not-array" }
+        end.should raise_error(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'])
+        data = DataSpecs::Measure.new(amount: 42, unit: 'km')
+
+        data.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'])
+        data = DataSpecs::Measure.new(amount: 42, unit: 'km')
+
+        -> do
+          data.to_h { |k| x }
+        end.should raise_error(TypeError, /wrong element type MockObject/)
+      end
+    end
+  end
+end