require File.expand_path('../../spec_helper', __FILE__) describe 'Optional variable assignments' do describe 'using ||=' do describe 'using a single variable' do it 'assigns a new variable' do a ||= 10 a.should == 10 end it 're-assigns an existing variable set to false' do a = false a ||= 10 a.should == 10 end it 're-assigns an existing variable set to nil' do a = nil a ||= 10 a.should == 10 end it 'does not re-assign a variable with a truthy value' do a = 10 a ||= 20 a.should == 10 end it 'does not evaluate the right side when not needed' do a = 10 a ||= raise('should not be executed') a.should == 10 end it 'does not re-assign a variable with a truthy value when using an inline rescue' do a = 10 a ||= 20 rescue 30 a.should == 10 end end describe 'using a accessor' do before do klass = Class.new { attr_accessor :b } @a = klass.new end it 'assigns a new variable' do @a.b ||= 10 @a.b.should == 10 end it 're-assigns an existing variable set to false' do @a.b = false @a.b ||= 10 @a.b.should == 10 end it 're-assigns an existing variable set to nil' do @a.b = nil @a.b ||= 10 @a.b.should == 10 end it 'does not re-assign a variable with a truthy value' do @a.b = 10 @a.b ||= 20 @a.b.should == 10 end it 'does not evaluate the right side when not needed' do @a.b = 10 @a.b ||= raise('should not be executed') @a.b.should == 10 end it 'does not re-assign a variable with a truthy value when using an inline rescue' do @a.b = 10 @a.b ||= 20 rescue 30 @a.b.should == 10 end end end describe 'using &&=' do describe 'using a single variable' do it 'leaves new variable unassigned' do a &&= 10 a.should == nil end it 'leaves false' do a = false a &&= 10 a.should == false end it 'leaves nil' do a = nil a &&= 10 a.should == nil end it 'does not evaluate the right side when not needed' do a = nil a &&= raise('should not be executed') a.should == nil end it 'does re-assign a variable with a truthy value' do a = 10 a &&= 20 a.should == 20 end it 'does re-assign a variable with a truthy value when using an inline rescue' do a = 10 a &&= 20 rescue 30 a.should == 20 end end describe 'using a single variable' do before do klass = Class.new { attr_accessor :b } @a = klass.new end it 'leaves new variable unassigned' do @a.b &&= 10 @a.b.should == nil end it 'leaves false' do @a.b = false @a.b &&= 10 @a.b.should == false end it 'leaves nil' do @a.b = nil @a.b &&= 10 @a.b.should == nil end it 'does not evaluate the right side when not needed' do @a.b = nil @a.b &&= raise('should not be executed') @a.b.should == nil end it 'does re-assign a variable with a truthy value' do @a.b = 10 @a.b &&= 20 @a.b.should == 20 end it 'does re-assign a variable with a truthy value when using an inline rescue' do @a.b = 10 @a.b &&= 20 rescue 30 @a.b.should == 20 end end end describe 'using compunded constants' do before do Object.send(:remove_const, :A) if defined? Object::A end it 'with ||= assignments' do Object::A ||= 10 Object::A.should == 10 end it 'with ||= do not reassign' do Object::A = 20 Object::A ||= 10 Object::A.should == 20 end it 'with &&= assignments' do Object::A = 20 -> { Object::A &&= 10 }.should complain(/already initialized constant/) Object::A.should == 10 end it 'with &&= assignments will fail with non-existent constants' do lambda { Object::A &&= 10 }.should raise_error(NameError) end it 'with operator assignments' do Object::A = 20 -> { Object::A += 10 }.should complain(/already initialized constant/) Object::A.should == 30 end it 'with operator assignments will fail with non-existent constants' do lambda { Object::A += 10 }.should raise_error(NameError) end end end