1 files changed, 42 insertions, 0 deletions
diff --git a/spec/ruby/library/matrix/minus_spec.rb b/spec/ruby/library/matrix/minus_spec.rb
new file mode 100644
index 0000000000..7426aa2d2c
--- /dev/null
+++ b/spec/ruby/library/matrix/minus_spec.rb
@@ -0,0 +1,42 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+require 'matrix'
+
+describe "Matrix#-" do
+  before :each do
+    @a = Matrix[ [1, 2], [3, 4] ]
+    @b = Matrix[ [4, 5], [6, 7] ]
+  end
+
+  it "returns the result of subtracting the corresponding elements of other from self" do
+    (@a - @b).should == Matrix[ [-3,-3], [-3,-3] ]
+  end
+
+  it "returns an instance of Matrix" do
+    (@a - @b).should.is_a?(Matrix)
+  end
+
+  it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
+    -> { @a - Matrix[ [1] ] }.should.raise(Matrix::ErrDimensionMismatch)
+  end
+
+  it "raises a ExceptionForMatrix::ErrOperationNotDefined if other is a Numeric Type" do
+    -> { @a - 2            }.should.raise(Matrix::ErrOperationNotDefined)
+    -> { @a - 1.2          }.should.raise(Matrix::ErrOperationNotDefined)
+    -> { @a - bignum_value }.should.raise(Matrix::ErrOperationNotDefined)
+  end
+
+  it "raises a TypeError if other is of wrong type" do
+    -> { @a - nil        }.should.raise(TypeError)
+    -> { @a - "a"        }.should.raise(TypeError)
+    -> { @a - [ [1, 2] ] }.should.raise(TypeError)
+    -> { @a - Object.new }.should.raise(TypeError)
+  end
+
+  describe "for a subclass of Matrix" do
+    it "returns an instance of that subclass" do
+      m = MatrixSub.ins
+      (m-m).should.instance_of?(MatrixSub)
+    end
+  end
+end