1 files changed, 71 insertions, 0 deletions
diff --git a/spec/ruby/core/hash/transform_values_spec.rb b/spec/ruby/core/hash/transform_values_spec.rb
new file mode 100644
index 0000000000..7e4ff45bea
--- /dev/null
+++ b/spec/ruby/core/hash/transform_values_spec.rb
@@ -0,0 +1,71 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+ruby_version_is "2.4" do
+  describe "Hash#transform_values" do
+    before :each do
+      @hash = { a: 1, b: 2, c: 3 }
+    end
+
+    it "returns new hash" do
+      ret = @hash.transform_values(&:succ)
+      ret.should_not equal(@hash)
+      ret.should be_an_instance_of(Hash)
+    end
+
+    it "sets the result as transformed values with the given block" do
+      @hash.transform_values(&:succ).should ==  { a: 2, b: 3, c: 4 }
+    end
+
+    context "when no block is given" do
+      it "returns a sized Enumerator" do
+        enumerator = @hash.transform_values
+        enumerator.should be_an_instance_of(Enumerator)
+        enumerator.size.should == @hash.size
+        enumerator.each(&:succ).should == { a: 2, b: 3, c: 4 }
+      end
+    end
+  end
+
+  describe "Hash#transform_values!" do
+    before :each do
+      @hash = { a: 1, b: 2, c: 3 }
+      @initial_pairs = @hash.dup
+    end
+
+    it "returns self" do
+      @hash.transform_values!(&:succ).should equal(@hash)
+    end
+
+    it "updates self as transformed values with the given block" do
+      @hash.transform_values!(&:succ)
+      @hash.should ==  { a: 2, b: 3, c: 4 }
+    end
+
+    context "when no block is given" do
+      it "returns a sized Enumerator" do
+        enumerator = @hash.transform_values!
+        enumerator.should be_an_instance_of(Enumerator)
+        enumerator.size.should == @hash.size
+        enumerator.each(&:succ)
+        @hash.should == { a: 2, b: 3, c: 4 }
+      end
+    end
+
+    describe "on frozen instance" do
+      before :each do
+        @hash.freeze
+      end
+
+      it "keeps pairs and raises a RuntimeError" do
+        ->{ @hash.transform_values!(&:succ) }.should raise_error(RuntimeError)
+        @hash.should == @initial_pairs
+      end
+
+      context "when no block is given" do
+        it "does not raise an exception" do
+          @hash.transform_values!.should be_an_instance_of(Enumerator)
+        end
+      end
+    end
+  end
+end