1 files changed, 20 insertions, 9 deletions
diff --git a/spec/ruby/library/matrix/exponent_spec.rb b/spec/ruby/library/matrix/exponent_spec.rb
index 188a1b34d2..4cbe63587d 100644
--- a/spec/ruby/library/matrix/exponent_spec.rb
+++ b/spec/ruby/library/matrix/exponent_spec.rb
@@ -1,5 +1,5 @@
-require File.expand_path('../../../spec_helper', __FILE__)
-require File.expand_path('../fixtures/classes', __FILE__)
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 require 'matrix'
 
 describe "Matrix#**" do
@@ -17,21 +17,32 @@ describe "Matrix#**" do
 
     it "raises a ErrDimensionMismatch for non square matrices" do
       m = Matrix[ [1, 1], [1, 2], [2, 3]]
-      lambda { m ** 3 }.should raise_error(Matrix::ErrDimensionMismatch)
-      lambda { m ** 0 }.should raise_error(Matrix::ErrDimensionMismatch)
+      -> { m ** 3 }.should.raise(Matrix::ErrDimensionMismatch)
+      -> { m ** 0 }.should.raise(Matrix::ErrDimensionMismatch)
     end
 
-    describe "that is <= 0" do
+    describe "that is < 0" do
       it "returns the inverse of **(-n)" do
         m = Matrix[ [1, 1], [1, 2] ]
         (m ** -2).should == Matrix[ [5, -3], [-3, 2]]
         (m ** -4).should == (m.inverse ** 4)
       end
 
-      it "raises a ErrDimensionMismatch for irregular matrices" do
+      it "raises a ErrNotRegular for irregular matrices" do
         m = Matrix[ [1, 1], [1, 1] ]
-        lambda { m ** -2 }.should raise_error(Matrix::ErrNotRegular)
-        lambda { m ** 0 }.should raise_error(Matrix::ErrNotRegular)
+        -> { m ** -2 }.should.raise(Matrix::ErrNotRegular)
+      end
+    end
+
+    describe "that is 0" do
+      it "returns the identity for square matrices" do
+        m = Matrix[ [1, 1], [1, 1] ]
+        (m ** 0).should == Matrix.identity(2)
+      end
+
+      it "raises an ErrDimensionMismatch for non-square matrices" do
+        m = Matrix[ [1, 1] ]
+        -> { m ** 0 }.should.raise(Matrix::ErrDimensionMismatch)
       end
     end
   end
@@ -45,7 +56,7 @@ describe "Matrix#**" do
 
   describe "for a subclass of Matrix" do
     it "returns an instance of that subclass" do
-      (MatrixSub.ins ** 1).should be_an_instance_of(MatrixSub)
+      (MatrixSub.ins ** 1).should.instance_of?(MatrixSub)
     end
   end
 end