Corregido Rakefile
Creada la expectativa de que debe ser cuadrada la matriz.

Failures:

  1) Matriz Debe comprobar que la matriz es cuadrada
     Failure/Error: expect { Matriz.new([2,3,3],[3,4],[1,2,3]) }.to raise_error
       expected Exception but nothing was raised
     # ./spec/matrices_spec.rb:8:in `block (2 levels) in <top (required)>'

Finished in 0.00105 seconds
1 example, 1 failure

Failed examples:

rspec ./spec/matrices_spec.rb:7 # Matriz Debe comprobar que la matriz es cuadrada
Arreglada la expectativa de que la matriz debe ser cuadrada.

Finished in 0.00113 seconds
1 example, 0 failures
Creada expectativa de que se debe poder acceder a los elementos de la matriz

Failures:

  1) Matriz Debe poder accederse a los elementos de la matriz
     Failure/Error: @matriz[0][0].should eq(1)
     NoMethodError:
       undefined method `[]' for #<Matriz:0x0000000215dcc0>
     # ./spec/matrices_spec.rb:13:in `block (2 levels) in <top (required)>'

Finished in 0.00126 seconds
2 examples, 1 failure

Failed examples:

rspec ./spec/matrices_spec.rb:12 # Matriz Debe poder accederse a los elementos de la matriz
Arreglada la expectativa de que se debe poder acceder a los elementos de la matriz.

Finished in 0.00147 seconds
2 examples, 0 failures
Creada expectativa para la suma de dos matrices.

Failures:

  1) Matriz Debe sumar dos matrices
     Failure/Error: @matriz3 = @matriz+@matriz2
     NoMethodError:
       undefined method `+' for #<Matriz:0x0000000359b480>
     # ./spec/matrices_spec.rb:25:in `block (2 levels) in <top (required)>'

Finished in 0.00177 seconds
3 examples, 1 failure

Failed examples:

rspec ./spec/matrices_spec.rb:24 # Matriz Debe sumar dos matrices
Arreglada la expectativa de la suma de dos matrices.

Finished in 0.015 seconds
3 examples, 0 failures
Creada expectativa para la resta de dos matrices.

Failures:

  1) Matriz Debe restar dos matrices
     Failure/Error: @matriz3 = @matriz-@matriz2
     NoMethodError:
       undefined method `-' for #<Matriz:0x00000000fde1c0>
     # ./spec/matrices_spec.rb:39:in `block (2 levels) in <top (required)>'

Finished in 0.01531 seconds
4 examples, 1 failure

Failed examples:

rspec ./spec/matrices_spec.rb:38 # Matriz Debe restar dos matrices
Arreglada la expectativa de restar dos matrices.

Finished in 0.01514 seconds
4 examples, 0 failures
Creada expectativa para la multiplicacion de dos matrices.

Failures:

  1) Matriz Debe multiplicar dos matrices
     Failure/Error: @matriz3 = @matriz*@matriz2
     NoMethodError:
       undefined method `*' for #<Matriz:0x000000012aa458>
     # ./spec/matrices_spec.rb:52:in `block (2 levels) in <top (required)>'

Finished in 0.01544 seconds
5 examples, 1 failure

Failed examples:

rspec ./spec/matrices_spec.rb:51 # Matriz Debe multiplicar dos matrices
Arreglada la expectativa para la multiplicacion de dos matrices cuadradas.

Finished in 0.0154 seconds
5 examples, 0 failures