Add in-tree mspec and ruby/spec

* For easier modifications of ruby/spec by MRI developers.
* .gitignore: track changes under spec.
* spec/mspec, spec/rubyspec: add in-tree mspec and ruby/spec.
  These files can therefore be updated like any other file in MRI.
  Instructions are provided in spec/README.
  [Feature #13156] [ruby-core:79246]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58595 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 81 insertions, 0 deletions

diff --git a/spec/rubyspec/core/enumerable/min_by_spec.rb b/spec/rubyspec/core/enumerable/min_by_spec.rb
new file mode 100644
index 0000000000..24fe995f09
--- /dev/null
+++ b/spec/rubyspec/core/enumerable/min_by_spec.rb
@@ -0,0 +1,81 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+require File.expand_path('../shared/enumerable_enumeratorized', __FILE__)
+
+describe "Enumerable#min_by" do
+  it "returns an enumerator if no block" do
+    EnumerableSpecs::Numerous.new(42).min_by.should be_an_instance_of(Enumerator)
+  end
+
+  it "returns nil if #each yields no objects" do
+    EnumerableSpecs::Empty.new.min_by {|o| o.nonesuch }.should == nil
+  end
+
+  it "returns the object for whom the value returned by block is the smallest" do
+    EnumerableSpecs::Numerous.new(*%w[3 2 1]).min_by {|obj| obj.to_i }.should == '1'
+    EnumerableSpecs::Numerous.new(*%w[five three]).min_by {|obj| obj.length }.should == 'five'
+  end
+
+  it "returns the object that appears first in #each in case of a tie" do
+    a, b, c = '2', '1', '1'
+    EnumerableSpecs::Numerous.new(a, b, c).min_by {|obj| obj.to_i }.should equal(b)
+  end
+
+  it "uses min.<=>(current) to determine order" do
+    a, b, c = (1..3).map{|n| EnumerableSpecs::ReverseComparable.new(n)}
+
+    # Just using self here to avoid additional complexity
+    EnumerableSpecs::Numerous.new(a, b, c).min_by {|obj| obj }.should == c
+  end
+
+  it "is able to return the minimum for enums that contain nils" do
+    enum = EnumerableSpecs::Numerous.new(nil, nil, true)
+    enum.min_by {|o| o.nil? ? 0 : 1 }.should == nil
+    enum.min_by {|o| o.nil? ? 1 : 0 }.should == true
+  end
+
+  it "gathers whole arrays as elements when each yields multiple" do
+    multi = EnumerableSpecs::YieldsMulti.new
+    multi.min_by {|e| e.size}.should == [1, 2]
+  end
+
+  it_behaves_like :enumerable_enumeratorized_with_origin_size, :min_by
+
+  context "when called with an argument n" do
+    before :each do
+      @enum = EnumerableSpecs::Numerous.new(101, 55, 1, 20, 33, 500, 60)
+    end
+
+    context "without a block" do
+      it "returns an enumerator" do
+        @enum.min_by(2).should be_an_instance_of(Enumerator)
+      end
+    end
+
+    context "with a block" do
+      it "returns an array containing the minimum n elements based on the block's value" do
+        result = @enum.min_by(3) { |i| i.to_s }
+        result.should == [1, 101, 20]
+      end
+
+      context "on a enumerable of length x where x < n" do
+        it "returns an array containing the minimum n elements of length n" do
+          result = @enum.min_by(500) { |i| i.to_s }
+          result.length.should == 7
+        end
+      end
+
+      context "when n is negative" do
+        it "raises an ArgumentError" do
+          lambda { @enum.min_by(-1) { |i| i.to_s } }.should raise_error(ArgumentError)
+        end
+      end
+    end
+
+    context "when n is nil" do
+      it "returns the minimum element" do
+        @enum.min_by(nil) { |i| i.to_s }.should == 1
+      end
+    end
+  end
+end