1 files changed, 75 insertions, 0 deletions
diff --git a/spec/ruby/core/integer/plus_spec.rb b/spec/ruby/core/integer/plus_spec.rb
new file mode 100644
index 0000000000..38428e56c5
--- /dev/null
+++ b/spec/ruby/core/integer/plus_spec.rb
@@ -0,0 +1,75 @@
+require_relative '../../spec_helper'
+require_relative 'shared/arithmetic_coerce'
+
+describe "Integer#+" do
+  it_behaves_like :integer_arithmetic_coerce_not_rescue, :+
+
+  context "fixnum" do
+    it "returns self plus the given Integer" do
+      (491 + 2).should == 493
+      (90210 + 10).should == 90220
+
+      (9 + bignum_value).should == 18446744073709551625
+      (1001 + 5.219).should == 1006.219
+    end
+
+    it "raises a TypeError when given a non-Integer" do
+      -> {
+        (obj = mock('10')).should_receive(:to_int).any_number_of_times.and_return(10)
+        13 + obj
+      }.should raise_error(TypeError)
+      -> { 13 + "10"    }.should raise_error(TypeError)
+      -> { 13 + :symbol }.should raise_error(TypeError)
+    end
+  end
+
+  context "bignum" do
+    before :each do
+      @bignum = bignum_value(76)
+    end
+
+    it "returns self plus the given Integer" do
+      (@bignum + 4).should == 18446744073709551696
+      (@bignum + 4.2).should be_close(18446744073709551696.2, TOLERANCE)
+      (@bignum + bignum_value(3)).should == 36893488147419103311
+    end
+
+    it "raises a TypeError when given a non-Integer" do
+      -> { @bignum + mock('10') }.should raise_error(TypeError)
+      -> { @bignum + "10" }.should raise_error(TypeError)
+      -> { @bignum + :symbol}.should raise_error(TypeError)
+    end
+  end
+
+  it "can be redefined" do
+    code = <<~RUBY
+      class Integer
+        alias_method :old_plus, :+
+        def +(other)
+          self - other
+        end
+      end
+      result = 1 + 2
+      Integer.alias_method :+, :old_plus
+      print result
+    RUBY
+    ruby_exe(code).should == "-1"
+  end
+
+  it "coerces the RHS and calls #coerce" do
+    obj = mock("integer plus")
+    obj.should_receive(:coerce).with(6).and_return([6, 3])
+    (6 + obj).should == 9
+  end
+
+  it "coerces the RHS and calls #coerce even if it's private" do
+    obj = Object.new
+    class << obj
+      private def coerce(n)
+        [n, 3]
+      end
+    end
+
+    (6 + obj).should == 9
+  end
+end