1 files changed, 34 insertions, 2 deletions
diff --git a/spec/ruby/library/matrix/inverse_spec.rb b/spec/ruby/library/matrix/inverse_spec.rb
index fa3fa7de8a..38b01b28fb 100644
--- a/spec/ruby/library/matrix/inverse_spec.rb
+++ b/spec/ruby/library/matrix/inverse_spec.rb
@@ -1,7 +1,39 @@
 require_relative '../../spec_helper'
 require_relative 'spec_helper'
-require_relative 'shared/inverse'
+require_relative 'fixtures/classes'
+require 'matrix'
 
 describe "Matrix#inverse" do
-  it_behaves_like :inverse, :inverse
+  it "returns a Matrix" do
+    Matrix[ [1,2], [2,1] ].inverse.should.instance_of?(Matrix)
+  end
+
+  it "returns the inverse of the Matrix" do
+    Matrix[
+      [1, 3, 3],     [1, 4, 3],  [1, 3, 4]
+    ].inverse.should ==
+    Matrix[
+      [7, -3, -3],   [-1, 1, 0], [-1, 0, 1]
+    ]
+  end
+
+  it "returns the inverse of the Matrix (other case)" do
+    Matrix[
+      [1, 2, 3],    [0, 1, 4],     [5, 6, 0]
+    ].inverse.should be_close_to_matrix([
+      [-24, 18, 5], [20, -15, -4], [-5, 4, 1]
+    ])
+  end
+
+  it "raises a ErrDimensionMismatch if the Matrix is not square" do
+    ->{
+      Matrix[ [1,2,3], [1,2,3] ].inverse
+    }.should.raise(Matrix::ErrDimensionMismatch)
+  end
+
+  describe "for a subclass of Matrix" do
+    it "returns an instance of that subclass" do
+      MatrixSub.ins.inverse.should.instance_of?(MatrixSub)
+    end
+  end
 end