1 files changed, 40 insertions, 6 deletions
diff --git a/spec/ruby/core/hash/to_h_spec.rb b/spec/ruby/core/hash/to_h_spec.rb
index 40bd0d06d2..d6eaac9f33 100644
--- a/spec/ruby/core/hash/to_h_spec.rb
+++ b/spec/ruby/core/hash/to_h_spec.rb
@@ -7,12 +7,6 @@ describe "Hash#to_h" do
     h.to_h.should equal(h)
   end
 
-  ruby_version_is "2.6" do
-    it "converts [key, value] pairs returned by the block to a hash" do
-      {a: 1, b: 2}.to_h {|k, v| [k.to_s, v*v]}.should == { "a" => 1, "b" => 4 }
-    end
-  end
-
   describe "when called on a subclass of Hash" do
     before :each do
       @h = HashSpecs::MyHash.new
@@ -37,4 +31,44 @@ describe "Hash#to_h" do
       @h[42].should == 84
     end
   end
+
+  ruby_version_is "2.6" do
+    context "with block" do
+      it "converts [key, value] pairs returned by the block to a hash" do
+        { a: 1, b: 2 }.to_h { |k, v| [k.to_s, v*v]}.should == { "a" => 1, "b" => 4 }
+      end
+
+      it "raises ArgumentError if block returns longer or shorter array" do
+        -> do
+          { a: 1, b: 2 }.to_h { |k, v| [k.to_s, v*v, 1] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+
+        -> do
+          { a: 1, b: 2 }.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
+        -> do
+          { a: 1, b: 2 }.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'])
+
+        { a: 1 }.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
+          { a: 1 }.to_h { |k| x }
+        end.should raise_error(TypeError, /wrong element type MockObject/)
+      end
+    end
+  end
 end