ruby--ruby/spec/ruby/library/matrix/build_spec.rb

require_relative '../../spec_helper'

ruby_version_is ""..."3.1" do
  require_relative 'fixtures/classes'
  require 'matrix'

  describe "Matrix.build" do

    it "returns a Matrix object of the given size" do
      m = Matrix.build(3, 4){1}
      m.should be_an_instance_of(Matrix)
      m.row_size.should == 3
      m.column_size.should == 4
    end

    it "builds the Matrix using the given block" do
      Matrix.build(2, 3){|col, row| 10*col - row}.should ==
        Matrix[[0, -1, -2], [10, 9, 8]]
    end

    it "iterates through the first row, then the second, ..." do
      acc = []
      Matrix.build(2, 3){|*args| acc << args}
      acc.should == [[0, 0], [0, 1], [0, 2], [1, 0], [1, 1], [1, 2]]
    end

    it "returns an Enumerator is no block is given" do
      enum = Matrix.build(2, 1)
      enum.should be_an_instance_of(Enumerator)
      enum.each{1}.should == Matrix[[1], [1]]
    end

    it "requires integers as parameters" do
      -> { Matrix.build("1", "2"){1} }.should raise_error(TypeError)
      -> { Matrix.build(nil, nil){1} }.should raise_error(TypeError)
      -> { Matrix.build(1..2){1} }.should raise_error(TypeError)
    end

    it "requires non-negative integers" do
      -> { Matrix.build(-1, 1){1} }.should raise_error(ArgumentError)
      -> { Matrix.build(+1,-1){1} }.should raise_error(ArgumentError)
    end

    it "returns empty Matrix if one argument is zero" do
      m = Matrix.build(0, 3){
        raise "Should not yield"
      }
      m.should be_empty
      m.column_size.should == 3

      m = Matrix.build(3, 0){
        raise "Should not yield"
      }
      m.should be_empty
      m.row_size.should == 3
    end

    it "tries to calls :to_int on arguments" do
      int = mock('int')
      int.should_receive(:to_int).twice.and_return(2)
      Matrix.build(int, int){ 1 }.should == Matrix[ [1,1], [1,1] ]
    end

    it "builds an nxn Matrix when given only one argument" do
      m = Matrix.build(3){1}
      m.row_size.should == 3
      m.column_size.should == 3
    end
  end

  describe "for a subclass of Matrix" do
    it "returns an instance of that subclass" do
      MatrixSub.build(3){1}.should be_an_instance_of(MatrixSub)
    end
  end
end