1 files changed, 270 insertions, 0 deletions
diff --git a/spec/ruby/core/module/include_spec.rb b/spec/ruby/core/module/include_spec.rb
new file mode 100644
index 0000000000..e5d19fc820
--- /dev/null
+++ b/spec/ruby/core/module/include_spec.rb
@@ -0,0 +1,270 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Module#include" do
+  it "is a public method" do
+    Module.should have_public_instance_method(:include, false)
+  end
+
+  it "calls #append_features(self) in reversed order on each module" do
+    $appended_modules = []
+
+    m = Module.new do
+      def self.append_features(mod)
+        $appended_modules << [ self, mod ]
+      end
+    end
+
+    m2 = Module.new do
+      def self.append_features(mod)
+        $appended_modules << [ self, mod ]
+      end
+    end
+
+    m3 = Module.new do
+      def self.append_features(mod)
+        $appended_modules << [ self, mod ]
+      end
+    end
+
+    c = Class.new { include(m, m2, m3) }
+
+    $appended_modules.should == [ [ m3, c], [ m2, c ], [ m, c ] ]
+  end
+
+  it "adds all ancestor modules when a previously included module is included again" do
+    ModuleSpecs::MultipleIncludes.ancestors.should include(ModuleSpecs::MA, ModuleSpecs::MB)
+    ModuleSpecs::MB.include(ModuleSpecs::MC)
+    ModuleSpecs::MultipleIncludes.include(ModuleSpecs::MB)
+    ModuleSpecs::MultipleIncludes.ancestors.should include(ModuleSpecs::MA, ModuleSpecs::MB, ModuleSpecs::MC)
+  end
+
+  it "raises a TypeError when the argument is not a Module" do
+    lambda { ModuleSpecs::Basic.include(Class.new) }.should raise_error(TypeError)
+  end
+
+  it "does not raise a TypeError when the argument is an instance of a subclass of Module" do
+    lambda { ModuleSpecs::SubclassSpec.include(ModuleSpecs::Subclass.new) }.should_not raise_error(TypeError)
+  end
+
+  it "imports constants to modules and classes" do
+    ModuleSpecs::A.constants.should include(:CONSTANT_A)
+    ModuleSpecs::B.constants.should include(:CONSTANT_A, :CONSTANT_B)
+    ModuleSpecs::C.constants.should include(:CONSTANT_A, :CONSTANT_B)
+  end
+
+  it "shadows constants from ancestors" do
+    klass = Class.new
+    klass.include ModuleSpecs::ShadowingOuter::M
+    klass::SHADOW.should == 123
+    klass.include ModuleSpecs::ShadowingOuter::N
+    klass::SHADOW.should == 456
+  end
+
+  it "does not override existing constants in modules and classes" do
+    ModuleSpecs::A::OVERRIDE.should == :a
+    ModuleSpecs::B::OVERRIDE.should == :b
+    ModuleSpecs::C::OVERRIDE.should == :c
+  end
+
+  it "imports instance methods to modules and classes" do
+    ModuleSpecs::A.instance_methods.should include(:ma)
+    ModuleSpecs::B.instance_methods.should include(:ma,:mb)
+    ModuleSpecs::C.instance_methods.should include(:ma,:mb)
+  end
+
+  it "does not import methods to modules and classes" do
+    ModuleSpecs::A.methods.include?(:cma).should == true
+    ModuleSpecs::B.methods.include?(:cma).should == false
+    ModuleSpecs::B.methods.include?(:cmb).should == true
+    ModuleSpecs::C.methods.include?(:cma).should == false
+    ModuleSpecs::C.methods.include?(:cmb).should == false
+  end
+
+  it "attaches the module as the caller's immediate ancestor" do
+    module IncludeSpecsTop
+      def value; 5; end
+    end
+
+    module IncludeSpecsMiddle
+      include IncludeSpecsTop
+      def value; 6; end
+    end
+
+    class IncludeSpecsClass
+      include IncludeSpecsMiddle
+    end
+
+    IncludeSpecsClass.new.value.should == 6
+  end
+
+  it "doesn't include module if it is included in a super class" do
+    module ModuleSpecs::M1
+      module M; end
+      class A; include M; end
+      class B < A; include M; end
+
+      all = [A,B,M]
+
+      (B.ancestors & all).should == [B, A, M]
+    end
+  end
+
+  it "recursively includes new mixins" do
+    module ModuleSpecs::M1
+      module U; end
+      module V; end
+      module W; end
+      module X; end
+      module Y; end
+      class A; include X; end;
+      class B < A; include U, V, W; end;
+
+      # update V
+      module V; include X, U, Y; end
+
+      # This code used to use Array#& and then compare 2 arrays, but
+      # the ordering from Array#& is undefined, as it uses Hash internally.
+      #
+      # Loop is more verbose, but more explicit in what we're testing.
+
+      anc = B.ancestors
+      [B, U, V, W, A, X].each do |i|
+        anc.include?(i).should be_true
+      end
+
+      class B; include V; end
+
+      # the only new module is Y, it is added after U since it follows U in V mixin list:
+      anc = B.ancestors
+      [B, U, Y, V, W, A, X].each do |i|
+        anc.include?(i).should be_true
+      end
+    end
+  end
+
+  it "preserves ancestor order" do
+    module ModuleSpecs::M2
+      module M1; end
+      module M2; end
+      module M3; include M2; end
+
+      module M2; include M1; end
+      module M3; include M2; end
+
+      M3.ancestors.should == [M3, M2, M1]
+
+    end
+  end
+
+  it "detects cyclic includes" do
+    lambda {
+      module ModuleSpecs::M
+        include ModuleSpecs::M
+      end
+    }.should raise_error(ArgumentError)
+  end
+
+  ruby_version_is ''...'2.4' do
+    it "accepts no-arguments" do
+      lambda {
+        Module.new do
+          include
+        end
+      }.should_not raise_error
+    end
+  end
+
+  ruby_version_is '2.4' do
+    it "doesn't accept no-arguments" do
+      lambda {
+        Module.new do
+          include
+        end
+      }.should raise_error(ArgumentError)
+    end
+  end
+
+  it "returns the class it's included into" do
+    m = Module.new
+    r = nil
+    c = Class.new { r = include m }
+    r.should == c
+  end
+
+  it "ignores modules it has already included via module mutual inclusion" do
+    module ModuleSpecs::AlreadyInc
+      module M0
+      end
+
+      module M
+        include M0
+      end
+
+      class K
+        include M
+        include M
+      end
+
+      K.ancestors[0].should == K
+      K.ancestors[1].should == M
+      K.ancestors[2].should == M0
+    end
+  end
+
+  it "clears any caches" do
+    module ModuleSpecs::M3
+      module M1
+        def foo
+          :m1
+        end
+      end
+
+      module M2
+        def foo
+          :m2
+        end
+      end
+
+      class C
+        include M1
+
+        def get
+          foo
+        end
+      end
+
+      c = C.new
+      c.get.should == :m1
+
+      class C
+        include M2
+      end
+
+      c.get.should == :m2
+
+      remove_const :C
+    end
+  end
+end
+
+describe "Module#include?" do
+  it "returns true if the given module is included by self or one of it's ancestors" do
+    ModuleSpecs::Super.include?(ModuleSpecs::Basic).should == true
+    ModuleSpecs::Child.include?(ModuleSpecs::Basic).should == true
+    ModuleSpecs::Child.include?(ModuleSpecs::Super).should == true
+    ModuleSpecs::Child.include?(Kernel).should == true
+
+    ModuleSpecs::Parent.include?(ModuleSpecs::Basic).should == false
+    ModuleSpecs::Basic.include?(ModuleSpecs::Super).should == false
+  end
+
+  it "returns false if given module is equal to self" do
+    ModuleSpecs.include?(ModuleSpecs).should == false
+  end
+
+  it "raises a TypeError when no module was given" do
+    lambda { ModuleSpecs::Child.include?("Test") }.should raise_error(TypeError)
+    lambda { ModuleSpecs::Child.include?(ModuleSpecs::Parent) }.should raise_error(TypeError)
+  end
+end