1 files changed, 44 insertions, 0 deletions
diff --git a/spec/rubyspec/core/struct/dig_spec.rb b/spec/rubyspec/core/struct/dig_spec.rb
new file mode 100644
index 0000000000..c222eec9e4
--- /dev/null
+++ b/spec/rubyspec/core/struct/dig_spec.rb
@@ -0,0 +1,44 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+ruby_version_is "2.3" do
+  describe "Struct#dig" do
+    before(:each) do
+      @klass = Struct.new(:a)
+      @instance = @klass.new(@klass.new({ b: [1, 2, 3] }))
+    end
+
+    it "returns the nested value specified by the sequence of keys" do
+      @instance.dig(:a, :a).should == { b: [1, 2, 3] }
+    end
+
+    it "returns the nested value specified if the sequence includes an index" do
+      @instance.dig(:a, :a, :b, 0).should == 1
+    end
+
+    it "returns nil if any intermediate step is nil" do
+      @instance.dig(:b, 0).should == nil
+    end
+
+    it "raises a TypeError if any intermediate step does not respond to #dig" do
+      instance = @klass.new(1)
+      lambda {
+        instance.dig(:a, 3)
+      }.should raise_error(TypeError)
+    end
+
+    it "raises an ArgumentError if no arguments provided" do
+      lambda { @instance.dig }.should raise_error(ArgumentError)
+    end
+
+    it "calls #dig on any intermediate step with the rest of the sequence as arguments" do
+      obj = Object.new
+      instance = @klass.new(obj)
+
+      def obj.dig(*args)
+        {dug: args}
+      end
+
+      instance.dig(:a, :bar, :baz).should == { dug: [:bar, :baz] }
+    end
+  end
+end