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|
require_relative '../spec_helper'
require_relative '../fixtures/constants'
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
it 'returns the new value if set to false' do
a = false
(a ||= 20).should == 20
end
it 'returns the original value if truthy' do
a = 10
(a ||= 20).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
it 'returns the new value if set to false' do
def @a.b=(x)
:v
end
@a.b = false
(@a.b ||= 20).should == 20
end
it 'returns the original value if truthy' do
def @a.b=(x)
@b = x
:v
end
@a.b = 10
(@a.b ||= 20).should == 10
end
it 'works when writer is private' do
klass = Class.new do
def t
self.b = false
(self.b ||= 10).should == 10
(self.b ||= 20).should == 10
end
def b
@b
end
def b=(x)
@b = x
:v
end
private :b=
end
klass.new.t
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
describe 'using a #[]' do
before do
@a = {}
klass = Class.new do
def [](k)
@hash ||= {}
@hash[k]
end
def []=(k, v)
@hash ||= {}
@hash[k] = v
7
end
end
@b = klass.new
end
it 'leaves new variable unassigned' do
@a[:k] &&= 10
@a.key?(:k).should == false
end
it 'leaves false' do
@a[:k] = false
@a[:k] &&= 10
@a[:k].should == false
end
it 'leaves nil' do
@a[:k] = nil
@a[:k] &&= 10
@a[:k].should == nil
end
it 'does not evaluate the right side when not needed' do
@a[:k] = nil
@a[:k] &&= raise('should not be executed')
@a[:k].should == nil
end
it 'does re-assign a variable with a truthy value' do
@a[:k] = 10
@a[:k] &&= 20
@a[:k].should == 20
end
it 'does re-assign a variable with a truthy value when using an inline rescue' do
@a[:k] = 10
@a[:k] &&= 20 rescue 30
@a[:k].should == 20
end
it 'returns the assigned value, not the result of the []= method with ||=' do
(@b[:k] ||= 12).should == 12
end
it 'returns the assigned value, not the result of the []= method with +=' do
@b[:k] = 17
(@b[:k] += 12).should == 29
end
end
end
describe 'using compounded constants' do
before :each do
Object.send(:remove_const, :A) if defined? Object::A
end
after :each 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
-> { 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
-> { Object::A += 10 }.should raise_error(NameError)
end
end
end
describe 'Optional constant assignment' do
describe 'with ||=' do
it "assigns a scoped constant if previously undefined" do
ConstantSpecs.should_not have_constant(:OpAssignUndefined)
module ConstantSpecs
OpAssignUndefined ||= 42
end
ConstantSpecs::OpAssignUndefined.should == 42
ConstantSpecs::OpAssignUndefinedOutside ||= 42
ConstantSpecs::OpAssignUndefinedOutside.should == 42
ConstantSpecs.send(:remove_const, :OpAssignUndefined)
ConstantSpecs.send(:remove_const, :OpAssignUndefinedOutside)
end
it "assigns a global constant if previously undefined" do
OpAssignGlobalUndefined ||= 42
::OpAssignGlobalUndefinedExplicitScope ||= 42
OpAssignGlobalUndefined.should == 42
::OpAssignGlobalUndefinedExplicitScope.should == 42
Object.send :remove_const, :OpAssignGlobalUndefined
Object.send :remove_const, :OpAssignGlobalUndefinedExplicitScope
end
it 'correctly defines non-existing constants' do
ConstantSpecs::ClassA::OR_ASSIGNED_CONSTANT1 ||= :assigned
ConstantSpecs::ClassA::OR_ASSIGNED_CONSTANT1.should == :assigned
end
it 'correctly overwrites nil constants' do
suppress_warning do # already initialized constant
ConstantSpecs::ClassA::NIL_OR_ASSIGNED_CONSTANT1 = nil
ConstantSpecs::ClassA::NIL_OR_ASSIGNED_CONSTANT1 ||= :assigned
ConstantSpecs::ClassA::NIL_OR_ASSIGNED_CONSTANT1.should == :assigned
end
end
it 'causes side-effects of the module part to be applied only once (for undefined constant)' do
x = 0
(x += 1; ConstantSpecs::ClassA)::OR_ASSIGNED_CONSTANT2 ||= :assigned
x.should == 1
ConstantSpecs::ClassA::OR_ASSIGNED_CONSTANT2.should == :assigned
end
it 'causes side-effects of the module part to be applied (for nil constant)' do
suppress_warning do # already initialized constant
ConstantSpecs::ClassA::NIL_OR_ASSIGNED_CONSTANT2 = nil
x = 0
(x += 1; ConstantSpecs::ClassA)::NIL_OR_ASSIGNED_CONSTANT2 ||= :assigned
x.should == 1
ConstantSpecs::ClassA::NIL_OR_ASSIGNED_CONSTANT2.should == :assigned
end
end
it 'does not evaluate the right-hand side if the module part raises an exception (for undefined constant)' do
x = 0
y = 0
-> {
(x += 1; raise Exception; ConstantSpecs::ClassA)::OR_ASSIGNED_CONSTANT3 ||= (y += 1; :assigned)
}.should raise_error(Exception)
x.should == 1
y.should == 0
defined?(ConstantSpecs::ClassA::OR_ASSIGNED_CONSTANT3).should == nil
end
it 'does not evaluate the right-hand side if the module part raises an exception (for nil constant)' do
ConstantSpecs::ClassA::NIL_OR_ASSIGNED_CONSTANT3 = nil
x = 0
y = 0
-> {
(x += 1; raise Exception; ConstantSpecs::ClassA)::NIL_OR_ASSIGNED_CONSTANT3 ||= (y += 1; :assigned)
}.should raise_error(Exception)
x.should == 1
y.should == 0
ConstantSpecs::ClassA::NIL_OR_ASSIGNED_CONSTANT3.should == nil
end
end
describe "with &&=" do
it "re-assigns a scoped constant if already true" do
module ConstantSpecs
OpAssignTrue = true
end
suppress_warning do
ConstantSpecs::OpAssignTrue &&= 1
end
ConstantSpecs::OpAssignTrue.should == 1
ConstantSpecs.send :remove_const, :OpAssignTrue
end
it "leaves scoped constant if not true" do
module ConstantSpecs
OpAssignFalse = false
end
ConstantSpecs::OpAssignFalse &&= 1
ConstantSpecs::OpAssignFalse.should == false
ConstantSpecs.send :remove_const, :OpAssignFalse
end
end
end
|
