9 files changed, 115 insertions, 7 deletions
diff --git a/spec/ruby/core/array/at_spec.rb b/spec/ruby/core/array/at_spec.rb
index e40c26f2cc..f2af0e13a1 100644
--- a/spec/ruby/core/array/at_spec.rb
+++ b/spec/ruby/core/array/at_spec.rb
@@ -15,7 +15,7 @@ describe "Array#at" do
     a.at(7).should == nil
   end
 
-  it "returns the (-n)'th elemet from the last, for the given negative index n" do
+  it "returns the (-n)'th element from the last, for the given negative index n" do
     a = [1, 2, 3, 4, 5, 6]
     a.at(-1).should == 6
     a.at(-2).should == 5
@@ -50,7 +50,7 @@ describe "Array#at" do
     lambda { [].at("cat") }.should raise_error(TypeError)
   end
 
-  it "raises an ArgumentError when 2 or more arguments is passed" do
+  it "raises an ArgumentError when 2 or more arguments are passed" do
     lambda { [:a, :b].at(0,1) }.should raise_error(ArgumentError)
   end
 end
diff --git a/spec/ruby/core/array/intersection_spec.rb b/spec/ruby/core/array/intersection_spec.rb
index 4d6c2a12d3..e399509ea7 100644
--- a/spec/ruby/core/array/intersection_spec.rb
+++ b/spec/ruby/core/array/intersection_spec.rb
@@ -19,7 +19,7 @@ describe "Array#&" do
 
   it "does not modify the original Array" do
     a = [1, 1, 3, 5]
-    a & [1, 2, 3]
+    (a & [1, 2, 3]).should == [1, 3]
     a.should == [1, 1, 3, 5]
   end
 
@@ -52,7 +52,7 @@ describe "Array#&" do
     obj1.stub!(:hash).and_return(0)
     obj2.stub!(:hash).and_return(0)
     obj1.should_receive(:eql?).at_least(1).and_return(true)
-    obj2.should_receive(:eql?).at_least(1).and_return(true)
+    obj2.stub!(:eql?).and_return(true)
 
     ([obj1] & [obj2]).should == [obj1]
     ([obj1, obj1, obj2, obj2] & [obj2]).should == [obj1]
diff --git a/spec/ruby/core/array/max_spec.rb b/spec/ruby/core/array/max_spec.rb
index cf6a48c2e3..db1d755645 100644
--- a/spec/ruby/core/array/max_spec.rb
+++ b/spec/ruby/core/array/max_spec.rb
@@ -1,6 +1,12 @@
 require File.expand_path('../../../spec_helper', __FILE__)
 
 describe "Array#max" do
+  ruby_version_is "2.4" do
+    it "is defined on Array" do
+      [1].method(:max).owner.should equal Array
+    end
+  end
+
   it "returns nil with no values" do
     [].max.should == nil
   end
diff --git a/spec/ruby/core/array/min_spec.rb b/spec/ruby/core/array/min_spec.rb
index 53fe4e0692..59f3814da2 100644
--- a/spec/ruby/core/array/min_spec.rb
+++ b/spec/ruby/core/array/min_spec.rb
@@ -1,6 +1,12 @@
 require File.expand_path('../../../spec_helper', __FILE__)
 
 describe "Array#min" do
+  ruby_version_is "2.4" do
+    it "is defined on Array" do
+      [1].method(:max).owner.should equal Array
+    end
+  end
+
   it "returns nil with no values" do
     [].min.should == nil
   end
diff --git a/spec/ruby/core/array/pack/buffer_spec.rb b/spec/ruby/core/array/pack/buffer_spec.rb
new file mode 100644
index 0000000000..928f7db731
--- /dev/null
+++ b/spec/ruby/core/array/pack/buffer_spec.rb
@@ -0,0 +1,52 @@
+# encoding: ascii-8bit
+
+require File.expand_path('../../../../spec_helper', __FILE__)
+
+ruby_version_is '2.4' do
+  describe "Aray#pack with `buffer` option" do
+    it "returns specified buffer" do
+      n = [ 65, 66, 67 ]
+      buffer = " "*3
+      result = n.pack("ccc", buffer: buffer)      #=> "ABC"
+      result.should equal(buffer)
+    end
+
+    it "adds result at the end of buffer content" do
+      n = [ 65, 66, 67 ] # result without buffer is "ABC"
+
+      buffer = ""
+      n.pack("ccc", buffer: buffer).should == "ABC"
+
+      buffer = "123"
+      n.pack("ccc", buffer: buffer).should == "123ABC"
+
+      buffer = "12345"
+      n.pack("ccc", buffer: buffer).should == "12345ABC"
+    end
+
+    it "raises TypeError exception if buffer is not String" do
+      lambda { [65].pack("ccc", buffer: []) }.should raise_error(
+        TypeError, "buffer must be String, not Array")
+    end
+
+    context "offset (@) is specified" do
+      it 'keeps buffer content if it is longer than offset' do
+        n = [ 65, 66, 67 ]
+        buffer = "123456"
+        n.pack("@3ccc", buffer: buffer).should == "123ABC"
+      end
+
+      it "fills the gap with \0 if buffer content is shorter than offset" do
+        n = [ 65, 66, 67 ]
+        buffer = "123"
+        n.pack("@6ccc", buffer: buffer).should == "123\0\0\0ABC"
+      end
+
+      it 'does not keep buffer content if it is longer than offset + result' do
+        n = [ 65, 66, 67 ]
+        buffer = "1234567890"
+        n.pack("@3ccc", buffer: buffer).should == "123ABC"
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/array/permutation_spec.rb b/spec/ruby/core/array/permutation_spec.rb
index 8a80b93c3b..c0eba57a3e 100644
--- a/spec/ruby/core/array/permutation_spec.rb
+++ b/spec/ruby/core/array/permutation_spec.rb
@@ -52,7 +52,7 @@ describe "Array#permutation" do
   end
 
   it "returns no permutations when the given length has no permutations" do
-    @numbers.permutation(9).entries.size == 0
+    @numbers.permutation(9).entries.size.should == 0
     @numbers.permutation(9) { |n| @yielded << n }
     @yielded.should == []
   end
diff --git a/spec/ruby/core/array/pop_spec.rb b/spec/ruby/core/array/pop_spec.rb
index 313dc4189e..ea649c6585 100644
--- a/spec/ruby/core/array/pop_spec.rb
+++ b/spec/ruby/core/array/pop_spec.rb
@@ -119,7 +119,7 @@ describe "Array#pop" do
       a.should == []
     end
 
-    it "raises a TypeError when the passed n can be coerced to Integer" do
+    it "raises a TypeError when the passed n cannot be coerced to Integer" do
       lambda{ [1, 2].pop("cat") }.should raise_error(TypeError)
       lambda{ [1, 2].pop(nil) }.should raise_error(TypeError)
     end
diff --git a/spec/ruby/core/array/shift_spec.rb b/spec/ruby/core/array/shift_spec.rb
index e5d25e2050..a7b6f58392 100644
--- a/spec/ruby/core/array/shift_spec.rb
+++ b/spec/ruby/core/array/shift_spec.rb
@@ -104,7 +104,7 @@ describe "Array#shift" do
       a.should == []
     end
 
-    it "raises a TypeError when the passed n can be coerced to Integer" do
+    it "raises a TypeError when the passed n cannot be coerced to Integer" do
       lambda{ [1, 2].shift("cat") }.should raise_error(TypeError)
       lambda{ [1, 2].shift(nil) }.should raise_error(TypeError)
     end
diff --git a/spec/ruby/core/array/sum_spec.rb b/spec/ruby/core/array/sum_spec.rb
new file mode 100644
index 0000000000..6548655c35
--- /dev/null
+++ b/spec/ruby/core/array/sum_spec.rb
@@ -0,0 +1,44 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+ruby_version_is '2.4' do
+  describe "Array#sum" do
+    it "returns the sum of elements" do
+      [1, 2, 3].sum.should == 6
+    end
+
+    it "applies a block to each element before adding if it's given" do
+      [1, 2, 3].sum { |i| i * 10 }.should == 60
+    end
+
+    it "returns init value if array is empty" do
+      [].sum(-1).should == -1
+    end
+
+    it "returns 0 if array is empty and init is omitted" do
+      [].sum.should == 0
+    end
+
+    it "adds init value to the sum of elemens" do
+      [1, 2, 3].sum(10).should == 16
+    end
+
+    it "can be used for non-numeric objects by providing init value" do
+      ["a", "b", "c"].sum("").should == "abc"
+    end
+
+    it 'raises TypeError if any element are not numeric' do
+      lambda { ["a"].sum }.should raise_error(TypeError)
+    end
+
+    it 'raises TypeError if any element cannot be added to init value' do
+      lambda { [1].sum([]) }.should raise_error(TypeError)
+    end
+
+    it "calls + to sum the elements" do
+      a = mock("a")
+      b = mock("b")
+      a.should_receive(:+).with(b).and_return(42)
+      [b].sum(a).should == 42
+    end
+  end
+end