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

spec/rubyspec/core/float/comparison_spec.rb

@@ -0,0 +1,36 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe "Float#<=>" do
+  it "returns -1, 0, 1 when self is less than, equal, or greater than other" do
+    (1.5 <=> 5).should == -1
+    (2.45 <=> 2.45).should == 0
+    ((bignum_value*1.1) <=> bignum_value).should == 1
+  end
+
+  it "returns nil when either argument is NaN" do
+    (nan_value <=> 71.2).should be_nil
+    (1771.176 <=> nan_value).should be_nil
+  end
+
+  it "returns nil when the given argument is not a Float" do
+    (1.0 <=> "1").should be_nil
+  end
+
+  # The 4 tests below are taken from matz's revision 23730 for Ruby trunk
+  #
+  it "returns 1 when self is Infinity and other is a Bignum" do
+    (infinity_value <=> Float::MAX.to_i*2).should == 1
+  end
+
+  it "returns -1 when self is negative and other is Infinty" do
+    (-Float::MAX.to_i*2 <=> infinity_value).should == -1
+  end
+
+  it "returns -1 when self is -Infinity and other is negative" do
+    (-infinity_value <=> -Float::MAX.to_i*2).should == -1
+  end
+
+  it "returns 1 when self is negative and other is -Infinity" do
+    (-Float::MAX.to_i*2 <=> -infinity_value).should == 1
+  end
+end