1 files changed, 19 insertions, 0 deletions
diff --git a/spec/ruby/library/matrix/shared/identity.rb b/spec/ruby/library/matrix/shared/identity.rb
new file mode 100644
index 0000000000..df957b5a75
--- /dev/null
+++ b/spec/ruby/library/matrix/shared/identity.rb
@@ -0,0 +1,19 @@
+require_relative '../fixtures/classes'
+require 'matrix'
+
+describe :matrix_identity, shared: true do
+  it "returns a Matrix" do
+    Matrix.send(@method, 2).should.is_a?(Matrix)
+  end
+
+  it "returns a n x n identity matrix" do
+    Matrix.send(@method, 3).should == Matrix.scalar(3, 1)
+    Matrix.send(@method, 100).should == Matrix.scalar(100, 1)
+  end
+
+  describe "for a subclass of Matrix" do
+    it "returns an instance of that subclass" do
+      MatrixSub.send(@method, 2).should.instance_of?(MatrixSub)
+    end
+  end
+end