ruby--ruby/spec/ruby/core/module/refine_spec.rb

require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/refine', __FILE__)

describe "Module#refine" do
  it "runs its block in an anonymous module" do
    inner_self = nil
    mod = Module.new do
      refine String do
        inner_self = self
      end
    end

    mod.should_not == inner_self
    inner_self.should be_kind_of(Module)
    inner_self.name.should == nil
  end

  it "uses the same anonymous module for future refines of the same class" do
    selves = []
    mod = Module.new do
      refine String do
        selves << self
      end
    end

    mod.module_eval do
      refine String do
        selves << self
      end
    end

    selves[0].should == selves[1]
  end

  it "adds methods defined in its block to the anonymous module's public instance methods" do
    inner_self = nil
    mod = Module.new do
      refine String do
        def blah
          "blah"
        end
        inner_self = self
      end
    end

    inner_self.public_instance_methods.should include(:blah)
  end

  it "returns created anonymous module" do
    inner_self = nil
    result = nil
    mod = Module.new do
      result = refine String do
        inner_self = self
      end
    end

    result.should == inner_self
  end

  it "raises ArgumentError if not passed an argument" do
    lambda do
      Module.new do
        refine {}
      end
    end.should raise_error(ArgumentError)
  end

  it "raises TypeError if not passed a class" do
    lambda do
      Module.new do
        refine("foo") {}
      end
    end.should raise_error(TypeError)
  end

  ruby_version_is "" ... "2.4" do
    it "raises TypeError if passed a module" do
      lambda do
        Module.new do
          refine(Enumerable) {}
        end
      end.should raise_error(TypeError)
    end
  end

  quarantine! do # https://bugs.ruby-lang.org/issues/14070
    ruby_version_is "2.4" do
      it "accepts a module as argument" do
        inner_self = nil
        Module.new do
          refine(Enumerable) do
            def blah
            end
            inner_self = self
          end
        end

        inner_self.public_instance_methods.should include(:blah)
      end
    end
  end

  it "raises ArgumentError if not given a block" do
    lambda do
      Module.new do
        refine String
      end
    end.should raise_error(ArgumentError)
  end

  it "applies refinements to calls in the refine block" do
    result = nil
    Module.new do
      refine(String) do
        def foo; "foo"; end
        result = "hello".foo
      end
    end
    result.should == "foo"
  end

  it "doesn't apply refinements outside the refine block" do
    Module.new do
      refine(String) {def foo; "foo"; end}
      -> () {
        "hello".foo
      }.should raise_error(NoMethodError)
    end
  end

  it "does not apply refinements to external scopes not using the module" do
    Module.new do
      refine(String) {def foo; 'foo'; end}
    end

    lambda {"hello".foo}.should raise_error(NoMethodError)
  end

  # When defining multiple refinements in the same module,
  # inside a refine block all refinements from the same
  # module are active when a refined method is called
  it "makes available all refinements from the same module" do
    refinement = Module.new do
      refine Integer do
        def to_json_format
          to_s
        end
      end

      refine Array do
        def to_json_format
          "[" + map { |i| i.to_json_format }.join(", ") + "]"
        end
      end

      refine Hash do
        def to_json_format
          "{" + map { |k, v| k.to_s.dump + ": " + v.to_json_format }.join(", ") + "}"
        end
      end
    end

    result = nil

    Module.new do
      using refinement

      result = [{1 => 2}, {3 => 4}].to_json_format
    end

    result.should == '[{"1": 2}, {"3": 4}]'
  end

  it "does not make available methods from another refinement module" do
    refinery_integer = Module.new do
      refine Integer do
        def to_json_format
          to_s
        end
      end
    end

    refinery_array = Module.new do
      refine Array do
        def to_json_format
          "[" + map { |i| i.to_json_format }.join(",") + "]"
        end
      end
    end

    result = nil

    -> () {
      Module.new do
        using refinery_integer
        using refinery_array

        [1, 2].to_json_format
      end
    }.should raise_error(NoMethodError)
  end

  # method lookup:
  #   * The prepended modules from the refinement for C
  #   * The refinement for C
  #   * The included modules from the refinement for C
  #   * The prepended modules of C
  #   * C
  #   * The included modules of C
  describe "method lookup" do
    it "looks in the object singleton class first" do
      refinement = Module.new do
        refine ModuleSpecs::ClassWithFoo  do
          def foo; "foo from refinement"; end
        end
      end

      result = nil
      Module.new do
        using refinement

        obj = ModuleSpecs::ClassWithFoo.new
        class << obj
          def foo; "foo from singleton class"; end
        end
        result = obj.foo
      end

      result.should == "foo from singleton class"
    end

    it "looks in prepended modules from the refinement first" do
      refinement = Module.new do
        refine ModuleSpecs::ClassWithFoo  do
          include ModuleSpecs::IncludedModule
          prepend ModuleSpecs::PrependedModule

          def foo; "foo from refinement"; end
        end
      end

      result = nil
      Module.new do
        using refinement
        result = ModuleSpecs::ClassWithFoo.new.foo
      end

      result.should == "foo from prepended module"
    end

    it "looks in refinement then" do
      refinement = Module.new do
        refine(ModuleSpecs::ClassWithFoo) do
          include ModuleSpecs::IncludedModule

          def foo; "foo from refinement"; end
        end
      end

      result = nil
      Module.new do
        using refinement
        result = ModuleSpecs::ClassWithFoo.new.foo
      end

      result.should == "foo from refinement"
    end

    it "looks in included modules from the refinement then" do
      refinement = Module.new do
        refine ModuleSpecs::ClassWithFoo  do
          include ModuleSpecs::IncludedModule
        end
      end

      result = nil
      Module.new do
        using refinement
        result = ModuleSpecs::ClassWithFoo.new.foo
      end

      result.should == "foo from included module"
    end

    it "looks in the class then" do
      refinement = Module.new do
        refine(ModuleSpecs::ClassWithFoo) { }
      end

      result = nil
      Module.new do
        using refinement
        result = ModuleSpecs::ClassWithFoo.new.foo
      end

      result.should == "foo"
    end
  end


  # methods in a subclass have priority over refinements in a superclass
  it "does not override methods in subclasses" do
    subclass = Class.new(ModuleSpecs::ClassWithFoo) do
      def foo; "foo from subclass"; end
    end

    refinement = Module.new do
      refine ModuleSpecs::ClassWithFoo do
        def foo; "foo from refinement"; end
      end
    end

    result = nil
    Module.new do
      using refinement
      result = subclass.new.foo
    end

    result.should == "foo from subclass"
  end

  context "for methods accesses indirectly" do
    ruby_version_is "" ... "2.4" do
      it "is not honored by Kernel#send" do
        refinement = Module.new do
          refine ModuleSpecs::ClassWithFoo do
            def foo; "foo from refinement"; end
          end
        end

        result = nil
        Module.new do
          using refinement
          result = ModuleSpecs::ClassWithFoo.new.send :foo
        end

        result.should == "foo"
      end

      it "is not honored by BasicObject#__send__" do
        refinement = Module.new do
          refine ModuleSpecs::ClassWithFoo do
            def foo; "foo from refinement"; end
          end
        end

        result = nil
        Module.new do
          using refinement
          result = ModuleSpecs::ClassWithFoo.new.__send__ :foo
        end

        result.should == "foo"
      end

      it "is not honored by Symbol#to_proc" do
        refinement = Module.new do
          refine Integer do
            def to_s
              "(#{super})"
            end
          end
        end

        result = nil
        Module.new do
          using refinement
          result = [1, 2, 3].map(&:to_s)
        end

        result.should == ["1", "2", "3"]
      end
    end

    ruby_version_is "2.4" do
      it "is honored by Kernel#send" do
        refinement = Module.new do
          refine ModuleSpecs::ClassWithFoo do
            def foo; "foo from refinement"; end
          end
        end

        result = nil
        Module.new do
          using refinement
          result = ModuleSpecs::ClassWithFoo.new.send :foo
        end

        result.should == "foo from refinement"
      end

      it "is honored by BasicObject#__send__" do
        refinement = Module.new do
          refine ModuleSpecs::ClassWithFoo do
            def foo; "foo from refinement"; end
          end
        end

        result = nil
        Module.new do
          using refinement
          result = ModuleSpecs::ClassWithFoo.new.__send__ :foo
        end

        result.should == "foo from refinement"
      end

      it "is honored by Symbol#to_proc" do
        refinement = Module.new do
          refine Integer do
            def to_s
              "(#{super})"
            end
          end
        end

        result = nil
        Module.new do
          using refinement
          result = [1, 2, 3].map(&:to_s)
        end

        result.should == ["(1)", "(2)", "(3)"]
      end
    end

    it "is honored by Kernel#binding" do
      refinement = Module.new do
        refine String do
          def to_s
            "hello from refinement"
          end
        end
      end

      klass = Class.new do
        using refinement

        def foo
          "foo".to_s
        end

        def get_binding
          binding
        end
      end

      result = Kernel.eval("self.foo()", klass.new.get_binding)
      result.should == "hello from refinement"
    end

    it "is not honored by Kernel#method" do
      klass = Class.new
      refinement = Module.new do
        refine klass do
          def foo; end
        end
      end

      -> {
        Module.new do
          using refinement
          klass.new.method(:foo)
        end
      }.should raise_error(NameError, /undefined method `foo'/)
    end

    it "is not honored by Kernel#respond_to?" do
      klass = Class.new
      refinement = Module.new do
        refine klass do
          def foo; end
        end
      end

      result = nil
      Module.new do
        using refinement
        result = klass.new.respond_to?(:foo)
      end

      result.should == false
    end
  end

  context "when super is called in a refinement" do
    it "looks in the included to refinery module" do
      refinement = Module.new do
        refine ModuleSpecs::ClassWithFoo  do
          include ModuleSpecs::IncludedModule

          def foo
            super
          end
        end
      end

      result = nil
      Module.new do
        using refinement
        result = ModuleSpecs::ClassWithFoo.new.foo
      end

      result.should == "foo from included module"
    end

    it "looks in the refined class" do
      refinement = Module.new do
        refine ModuleSpecs::ClassWithFoo  do
          def foo
            super
          end
        end
      end

      result = nil
      Module.new do
        using refinement
        result = ModuleSpecs::ClassWithFoo.new.foo
      end

      result.should == "foo"
    end

    # super in a method of a refinement invokes the method in the refined
    # class even if there is another refinement which has been activated
    # in the same context.
    it "looks in the refined class even if there is another active refinement" do
      refinement = Module.new do
        refine ModuleSpecs::ClassWithFoo  do
          def foo
            "foo from refinement"
          end
        end
      end

      refinement_with_super = Module.new do
        refine ModuleSpecs::ClassWithFoo  do
          def foo
            super
          end
        end
      end

      result = nil
      Module.new do
        using refinement
        using refinement_with_super
        result = ModuleSpecs::ClassWithFoo.new.foo
      end

      result.should == "foo"
    end
  end

  # Refinements are inherited by module inclusion.
  # That is, using activates all refinements in the ancestors of the specified module.
  # Refinements in a descendant have priority over refinements in an ancestor.
  context "module inclusion" do
    it "activates all refinements from all ancestors" do
      refinement_included = Module.new do
        refine Integer do
          def to_json_format
            to_s
          end
        end
      end

      refinement = Module.new do
        include refinement_included

        refine Array do
          def to_json_format
            "[" + map { |i| i.to_s }.join(", ") + "]"
          end
        end
      end

      result = nil
      Module.new do
        using refinement
        result = [5.to_json_format, [1, 2, 3].to_json_format]
      end

      result.should == ["5", "[1, 2, 3]"]
    end

    it "overrides methods of ancestors by methods in descendants" do
      refinement_included = Module.new do
        refine Integer do
          def to_json_format
            to_s
          end
        end
      end

      refinement = Module.new do
        include refinement_included

        refine Integer do
          def to_json_format
            "hello from refinement"
          end
        end
      end

      result = nil
      Module.new do
        using refinement
        result = 5.to_json_format
      end

      result.should == "hello from refinement"
    end
  end
end