require_relative '../../spec_helper'

describe "Struct#deconstruct_keys" do
  it "returns a hash of attributes" do
    struct = Struct.new(:x, :y)
    s = struct.new(1, 2)

    s.deconstruct_keys([:x, :y]).should == {x: 1, y: 2}
  end

  it "requires one argument" do
    struct = Struct.new(:x)
    obj = struct.new(1)

    -> {
      obj.deconstruct_keys
    }.should raise_error(ArgumentError, /wrong number of arguments \(given 0, expected 1\)/)
  end

  it "returns only specified keys" do
    struct = Struct.new(:x, :y, :z)
    s = struct.new(1, 2, 3)

    s.deconstruct_keys([:x, :y]).should == {x: 1, y: 2}
    s.deconstruct_keys([:x]    ).should == {x: 1}
    s.deconstruct_keys([]      ).should == {}
  end

  it "accepts string attribute names" do
    struct = Struct.new(:x, :y)
    s = struct.new(1, 2)

    s.deconstruct_keys(['x', 'y']).should == {'x' => 1, 'y' => 2}
  end

  it "accepts argument position number as well but returns them as keys" do
    struct = Struct.new(:x, :y, :z)
    s = struct.new(10, 20, 30)

    s.deconstruct_keys([0, 1, 2]).should == {0 => 10, 1 => 20, 2 => 30}
    s.deconstruct_keys([0, 1]   ).should == {0 => 10, 1 => 20}
    s.deconstruct_keys([0]      ).should == {0 => 10}
  end

  it "returns an empty hash when there are more keys than attributes" do
    struct = Struct.new(:x, :y)
    s = struct.new(1, 2)

    s.deconstruct_keys([:x, :y, :a]).should == {}
  end

  it "returns at first not existing attribute name" do
    struct = Struct.new(:x, :y)
    s = struct.new(1, 2)

    s.deconstruct_keys([:a, :x]).should == {}
    s.deconstruct_keys([:x, :a]).should == {x: 1}
  end

  it "accepts nil argument and return all the attributes" do
    struct = Struct.new(:x, :y)
    obj = struct.new(1, 2)

    obj.deconstruct_keys(nil).should == {x: 1, y: 2}
  end

  it "raise TypeError if passed anything accept nil or array" do
    struct = Struct.new(:x, :y)
    s = struct.new(1, 2)

    -> { s.deconstruct_keys('x') }.should raise_error(TypeError, /expected Array or nil/)
    -> { s.deconstruct_keys(1)   }.should raise_error(TypeError, /expected Array or nil/)
    -> { s.deconstruct_keys(:x)  }.should raise_error(TypeError, /expected Array or nil/)
    -> { s.deconstruct_keys({})  }.should raise_error(TypeError, /expected Array or nil/)
  end
end