test_refinement.rb

require 'test/unit'
require_relative 'envutil'

class TestRefinement < Test::Unit::TestCase
  class Foo
    def x
      return "Foo#x"
    end

    def y
      return "Foo#y"
    end

    def call_x
      return x
    end
  end

  module FooExt
    refine Foo do
      def x
        return "FooExt#x"
      end

      def y
        return "FooExt#y " + super
      end

      def z
        return "FooExt#z"
      end
    end
  end

  module FooExt2
    refine Foo do
      def x
        return "FooExt2#x"
      end

      def y
        return "FooExt2#y " + super
      end

      def z
        return "FooExt2#z"
      end
    end
  end

  class FooSub < Foo
    def x
      return "FooSub#x"
    end

    def y
      return "FooSub#y " + super
    end
  end

  class FooExtClient
    using FooExt

    def self.invoke_x_on(foo)
      return foo.x
    end

    def self.invoke_y_on(foo)
      return foo.y
    end

    def self.invoke_z_on(foo)
      return foo.z
    end

    def self.send_z_on(foo)
      return foo.send(:z)
    end

    def self.method_z(foo)
      return foo.method(:z)
    end

    def self.invoke_call_x_on(foo)
      return foo.call_x
    end
  end

  class FooExtClient2
    using FooExt
    using FooExt2

    def self.invoke_y_on(foo)
      return foo.y
    end
  end

  def test_override
    foo = Foo.new
    assert_equal("Foo#x", foo.x)
    assert_equal("FooExt#x", FooExtClient.invoke_x_on(foo))
    assert_equal("Foo#x", foo.x)
  end

  def test_super
    foo = Foo.new
    assert_equal("Foo#y", foo.y)
    assert_equal("FooExt#y Foo#y", FooExtClient.invoke_y_on(foo))
    assert_equal("Foo#y", foo.y)
  end

  def test_super_chain
    foo = Foo.new
    assert_equal("Foo#y", foo.y)
    assert_equal("FooExt2#y FooExt#y Foo#y", FooExtClient2.invoke_y_on(foo))
    assert_equal("Foo#y", foo.y)
  end

  def test_new_method
    foo = Foo.new
    assert_raise(NoMethodError) { foo.z }
    assert_equal("FooExt#z", FooExtClient.invoke_z_on(foo))
    assert_raise(NoMethodError) { foo.z }
  end

  def test_new_method_by_send
    foo = Foo.new
    assert_raise(NoMethodError) { foo.send(:z) }
    assert_equal("FooExt#z", FooExtClient.send_z_on(foo))
    assert_raise(NoMethodError) { foo.send(:z) }
  end

  def test_new_method_by_method_object
    foo = Foo.new
    assert_raise(NoMethodError) { foo.send(:z) }
    assert_equal("FooExt#z", FooExtClient.method_z(foo).call)
    assert_raise(NoMethodError) { foo.send(:z) }
  end

  def test_no_local_rebinding
    foo = Foo.new
    assert_equal("Foo#x", foo.call_x)
    assert_equal("Foo#x", FooExtClient.invoke_call_x_on(foo))
    assert_equal("Foo#x", foo.call_x)
  end

  def test_subclass_is_prior
    sub = FooSub.new
    assert_equal("FooSub#x", sub.x)
    assert_equal("FooSub#x", FooExtClient.invoke_x_on(sub))
    assert_equal("FooSub#x", sub.x)
  end

  def test_super_in_subclass
    sub = FooSub.new
    assert_equal("FooSub#y Foo#y", sub.y)
    # not "FooSub#y FooExt#y Foo#y"
    assert_equal("FooSub#y Foo#y", FooExtClient.invoke_y_on(sub))
    assert_equal("FooSub#y Foo#y", sub.y)
  end

  def test_new_method_on_subclass
    sub = FooSub.new
    assert_raise(NoMethodError) { sub.z }
    assert_equal("FooExt#z", FooExtClient.invoke_z_on(sub))
    assert_raise(NoMethodError) { sub.z }
  end

  def test_module_eval
    foo = Foo.new
    assert_equal("Foo#x", foo.x)
    assert_equal("FooExt#x", FooExt.module_eval { foo.x })
    assert_equal("Foo#x", foo.x)
  end

  def test_instance_eval
    foo = Foo.new
    ext_client = FooExtClient.new
    assert_equal("Foo#x", foo.x)
    assert_equal("FooExt#x", ext_client.instance_eval { foo.x })
    assert_equal("Foo#x", foo.x)
  end

  def test_override_builtin_method
    m = Module.new {
      refine Fixnum do
        def /(other) quo(other) end
      end
    }
    assert_equal(0, 1 / 2)
    assert_equal(Rational(1, 2), m.module_eval { 1 / 2 })
    assert_equal(0, 1 / 2)
  end

  def test_override_builtin_method_with_method_added
    m = Module.new {
      refine Fixnum do
        def self.method_added(*args); end
        def +(other) "overriden" end
      end
    }
    assert_equal(3, 1 + 2)
    assert_equal("overriden", m.module_eval { 1 + 2 })
    assert_equal(3, 1 + 2)
  end

  def test_return_value_of_refine
    mod = nil
    result = nil
    m = Module.new {
      result = refine(Object) {
        mod = self
      }
    }
    assert_equal mod, result
  end

  def test_refine_same_class_twice
    result1 = nil
    result2 = nil
    result3 = nil
    m = Module.new {
      result1 = refine(Fixnum) {
        def foo; return "foo" end
      }
      result2 = refine(Fixnum) {
        def bar; return "bar" end
      }
      result3 = refine(String) {
        def baz; return "baz" end
      }
    }
    assert_equal("foo", m.module_eval { 1.foo })
    assert_equal("bar", m.module_eval { 1.bar })
    assert_equal(result1, result2)
    assert_not_equal(result1, result3)
  end

  def test_respond_to?
    m = Module.new {
      refine Fixnum do
        def foo; "foo"; end
      end
    }
    assert_equal(false, 1.respond_to?(:foo))
    assert_equal(true, m.module_eval { 1.respond_to?(:foo) })
    assert_equal(false, 1.respond_to?(:foo))
  end

  def test_builtin_method_no_local_rebinding
    m = Module.new {
      refine String do
        def <=>(other) return 0 end
      end
    }
    assert_equal(false, m.module_eval { "1" >= "2" })

    m2 = Module.new {
      refine Array do
        def each
          super do |i|
            yield 2 * i
          end
        end
      end
    }
    a = [1, 2, 3]
    assert_equal(1, m2.module_eval { a.min })
  end

  def test_module_inclusion
    m1 = Module.new {
      def foo
        "m1#foo"
      end

      def bar
        "m1#bar"
      end
    }
    m2 = Module.new {
      def bar
        "m2#bar"
      end

      def baz
        "m2#baz"
      end
    }
    m3 = Module.new {
      def baz
        "m3#baz"
      end
    }
    include_proc = Proc.new {
      include m3, m2
    }
    m = Module.new {
      refine String do
        include m1
        module_eval(&include_proc)

        def call_foo
          foo
        end

        def call_bar
          bar
        end

        def call_baz
          baz
        end
      end

      def self.call_foo(s)
        s.foo
      end

      def self.call_bar(s)
        s.bar
      end

      def self.call_baz(s)
        s.baz
      end
    }
    assert_equal("m1#foo", m.module_eval { "abc".foo })
    assert_equal("m2#bar", m.module_eval { "abc".bar })
    assert_equal("m3#baz", m.module_eval { "abc".baz })
    assert_equal("m1#foo", m.module_eval { "abc".call_foo })
    assert_equal("m2#bar", m.module_eval { "abc".call_bar })
    assert_equal("m3#baz", m.module_eval { "abc".call_baz })
    assert_equal("m1#foo", m.call_foo("abc"))
    assert_equal("m2#bar", m.call_bar("abc"))
    assert_equal("m3#baz", m.call_baz("abc"))
  end

  def test_refine_prepended_class
    m1 = Module.new {
      def foo
        super << :m1
      end
    }
    c = Class.new {
      prepend m1

      def foo
        [:c]
      end
    }
    m2 = Module.new {
      refine c do
        def foo
          super << :m2
        end
      end
    }
    obj = c.new
    assert_equal([:c, :m1, :m2], m2.module_eval { obj.foo })
  end

  def test_refine_module_without_overriding
    m1 = Module.new
    c = Class.new {
      include m1
    }
    m2 = Module.new {
      refine m1 do
        def foo
          :m2
        end
      end
    }
    obj = c.new
    assert_equal(:m2, m2.module_eval { obj.foo })
  end

  def test_refine_module_with_overriding
    m1 = Module.new {
      def foo
        super << :m1
      end
    }
    c0 = Class.new {
      def foo
        [:c0]
      end
    }
    c = Class.new(c0) {
      include m1
    }
    m2 = Module.new {
      refine m1 do
        def foo
          super << :m2
        end
      end
    }
    obj = c.new
    assert_equal([:c0, :m1, :m2], m2.module_eval { obj.foo })
  end

  def test_refine_module_with_double_overriding
    m1 = Module.new {
      def foo
        [:m1]
      end
    }
    c = Class.new {
      include m1
    }
    m2 = Module.new {
      refine m1 do
        def foo
          super << :m2
        end
      end
    }
    m3 = Module.new {
      using m2
      refine m1 do
        def foo
          super << :m3
        end
      end
    }
    obj = c.new
    assert_equal([:m1, :m2, :m3], m3.module_eval { obj.foo })
  end

  def test_refine_module_and_call_superclass_method
    m1 = Module.new
    c1 = Class.new {
      def foo
        "c1#foo"
      end
    }
    c2 = Class.new(c1) {
      include m1
    }
    m2 = Module.new {
      refine m1 do
      end
    }
    obj = c2.new
    assert_equal("c1#foo", m2.module_eval { obj.foo })
  end

  def test_refine_neither_class_nor_module
    assert_raise(TypeError) do
      Module.new {
        refine Object.new do
        end
      }
    end
    assert_raise(TypeError) do
      Module.new {
        refine 123 do
        end
      }
    end
    assert_raise(TypeError) do
      Module.new {
        refine "foo" do
        end
      }
    end
  end

  def test_refine_in_class_and_class_eval
    c = Class.new {
      refine Fixnum do
        def foo
          "c"
        end
      end
    }
    assert_equal("c", c.class_eval { 123.foo })
  end

  def test_main_using
    assert_in_out_err([], <<-INPUT, %w(:C :M), [])
      class C
        def foo
          :C
        end
      end

      module M
        refine C do
          def foo
            :M
          end
        end
      end

      c = C.new
      p c.foo
      using M
      p c.foo
    INPUT
  end

  def test_no_kernel_using
    assert_raise(NoMethodError) do
      using Module.new
    end
  end

  def test_module_using_class
    c = Class.new
    m = Module.new
    assert_raise(TypeError) do
      m.module_eval do
        using c
      end
    end
  end

  def test_refinements_empty
    m = Module.new
    assert(m.refinements.empty?)
  end

  def test_refinements_one
    c = Class.new
    c_ext = nil
    m = Module.new {
      refine c do
        c_ext = self
      end
    }
    assert_equal({c => c_ext}, m.refinements)
  end

  def test_refinements_two
    c1 = Class.new
    c1_ext = nil
    c2 = Class.new
    c2_ext = nil
    m = Module.new {
      refine c1 do
        c1_ext = self
      end

      refine c2 do
        c2_ext = self
      end
    }
    assert_equal({c1 => c1_ext, c2 => c2_ext}, m.refinements)
  end

  def test_refinements_duplicate_refine
    c = Class.new
    c_ext = nil
    m = Module.new {
      refine c do
        c_ext = self
      end
      refine c do
      end
    }
    assert_equal({c => c_ext}, m.refinements)
  end

  def test_refinements_no_recursion
    c1 = Class.new
    c1_ext = nil
    m1 = Module.new {
      refine c1 do
        c1_ext = self
      end
    }
    c2 = Class.new
    c2_ext = nil
    m2 = Module.new {
      using m1
      refine c2 do
        c2_ext = self
      end
    }
    assert_equal({c2 => c2_ext}, m2.refinements)
  end

  def test_refine_without_block
    c1 = Class.new
    e = assert_raise(ArgumentError) {
      Module.new do
        refine c1
      end
    }
    assert_equal("no block given", e.message)
  end

  module IndirectUsing
    class C
    end

    module M1
      refine C do
        def m1
          :m1
        end
      end
    end

    module M2
      refine C do
        def m2
          :m2
        end
      end
    end

    module M3
      using M1
      using M2
    end

    module M
      using M3

      def self.call_m1
        C.new.m1
      end

      def self.call_m2
        C.new.m2
      end
    end
  end

  def test_indirect_using
    assert_equal(:m1, IndirectUsing::M.call_m1)
    assert_equal(:m2, IndirectUsing::M.call_m2)
  end

  def test_indirect_using_module_eval
    c = Class.new
    m1 = Module.new {
      refine c do
        def m1
          :m1
        end
      end
    }
    m2 = Module.new {
      refine c do
        def m2
          :m2
        end
      end
    }
    m3 = Module.new {
      using m1
      using m2
    }
    m = Module.new {
      using m3
    }
    assert_equal(:m1, m.module_eval { c.new.m1 })
    assert_equal(:m2, m.module_eval { c.new.m2 })
  end

  module SymbolToProc
    class C
    end

    module M
      refine C do
        def foo
          "foo"
        end
      end

      def self.call_foo
        c = C.new
        :foo.to_proc.call(c)
      end

      def self.foo_proc
        :foo.to_proc
      end
    end
  end

  def test_symbol_to_proc
    assert_equal("foo", SymbolToProc::M.call_foo)
    assert_equal("foo", SymbolToProc::M.foo_proc.call(SymbolToProc::C.new))
  end

  module Inspect
    module M
      refine Fixnum do
      end
    end
  end

  def test_inspect
    assert_equal("#<refinement:Fixnum@TestRefinement::Inspect::M>",
                 Inspect::M.refinements[Fixnum].inspect)

    c = Class.new
    m = Module.new {
      refine String do
      end
      refine c do
      end
    }
    assert_equal("#<refinement:String@#{m.inspect}>",
                 m.refinements[String].inspect)
    assert_equal("#<refinement:#{c.inspect}@#{m.inspect}>",
                 m.refinements[c].inspect)
  end

  module InlineMethodCache
    class C
      def foo
        "original"
      end
    end

    module M
      refine C do
        def foo
          "refined"
        end
      end
    end
  end

  def test_inline_method_cache
    c = InlineMethodCache::C.new
    f = Proc.new { c.foo }
    assert_equal("original", f.call)
    assert_equal("refined", InlineMethodCache::M.module_eval(&f))
    assert_equal("original", f.call)
  end

  module UsingMethodCache
    class C
      def foo
        "original"
      end
    end

    module M1
      refine C do
        def foo
          "M1"
        end
      end
    end

    module M2
      refine C do
        def foo
          "M2"
        end
      end
    end

    module M
      c = C.new
      ORIGINAL_FOO = c.foo
      using M1
      c.foo
      using M2
      M2_FOO = c.foo
    end
  end

  def test_using_method_cache
    assert_equal("original", UsingMethodCache::M::ORIGINAL_FOO)
    assert_equal("M2", UsingMethodCache::M::M2_FOO)

    assert_in_out_err([], <<-INPUT, %w(:M1 :M2), [])
      class C
        def foo
          "original"
        end
      end

      module M1
        refine C do
          def foo
            :M1
          end
        end
      end

      module M2
        refine C do
          def foo
            :M2
          end
        end
      end

      c = C.new
      using M1
      p c.foo
      using M2
      p c.foo
    INPUT
  end

  def test_circular_using_is_not_allowed
    a = Module.new
    b = Module.new

    assert_raise ArgumentError do
      a.module_eval do
        using a
      end
    end

    b.module_eval do
      using a
    end

    assert_raise ArgumentError do
      a.module_eval do
        using b
      end
    end
  end

  module RedifineRefinedMethod
    class C
      def foo
        "original"
      end
    end

    module M
      refine C do
        def foo
          "refined"
        end
      end
    end

    class C
      def foo
        "redefined"
      end
    end
  end

  def test_redefine_refined_method
    c = RedifineRefinedMethod::C.new
    assert_equal("refined", RedifineRefinedMethod::M.module_eval { c.foo })
  end
end