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 be_kind_of(Matrix) end it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do lambda { @a - Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch) end it "raises a ExceptionForMatrix::ErrOperationNotDefined if other is a Numeric Type" do lambda { @a - 2 }.should raise_error(Matrix::ErrOperationNotDefined) lambda { @a - 1.2 }.should raise_error(Matrix::ErrOperationNotDefined) lambda { @a - bignum_value }.should raise_error(Matrix::ErrOperationNotDefined) end it "raises a TypeError if other is of wrong type" do lambda { @a - nil }.should raise_error(TypeError) lambda { @a - "a" }.should raise_error(TypeError) lambda { @a - [ [1, 2] ] }.should raise_error(TypeError) lambda { @a - Object.new }.should raise_error(TypeError) end describe "for a subclass of Matrix" do it "returns an instance of that subclass" do m = MatrixSub.ins (m-m).should be_an_instance_of(MatrixSub) end end end