require_relative '../../spec_helper' require_relative 'fixtures/classes' describe "BasicObject#instance_exec" do it "is a public instance method" do BasicObject.should have_public_instance_method(:instance_exec) end it "sets self to the receiver in the context of the passed block" do a = BasicObject.new a.instance_exec { self }.equal?(a).should be_true end it "passes arguments to the block" do a = BasicObject.new a.instance_exec(1) { |b| b }.should equal(1) end it "raises a LocalJumpError unless given a block" do lambda { "hola".instance_exec }.should raise_error(LocalJumpError) end it "has an arity of -1" do Object.new.method(:instance_exec).arity.should == -1 end it "accepts arguments with a block" do lambda { "hola".instance_exec(4, 5) { |a,b| a + b } }.should_not raise_error end it "doesn't pass self to the block as an argument" do "hola".instance_exec { |o| o }.should be_nil end it "passes any arguments to the block" do Object.new.instance_exec(1,2) {|one, two| one + two}.should == 3 end it "only binds the exec to the receiver" do f = Object.new f.instance_exec do def foo 1 end end f.foo.should == 1 lambda { Object.new.foo }.should raise_error(NoMethodError) end # TODO: This should probably be replaced with a "should behave like" that uses # the many scoping/binding specs from kernel/eval_spec, since most of those # behaviors are the same for instance_exec. See also module_eval/class_eval. it "binds self to the receiver" do s = "hola" (s == s.instance_exec { self }).should == true end it "binds the block's binding self to the receiver" do s = "hola" (s == s.instance_exec { eval "self", binding }).should == true end it "executes in the context of the receiver" do "Ruby-fu".instance_exec { size }.should == 7 Object.class_eval { "Ruby-fu".instance_exec{ to_s } }.should == "Ruby-fu" end it "has access to receiver's instance variables" do BasicObjectSpecs::IVars.new.instance_exec { @secret }.should == 99 end it "sets class variables in the receiver" do BasicObjectSpecs::InstExec.class_variables.should include(:@@count) BasicObjectSpecs::InstExec.send(:class_variable_get, :@@count).should == 2 end it "raises a TypeError when defining methods on an immediate" do lambda do 1.instance_exec { def foo; end } end.should raise_error(TypeError) lambda do :foo.instance_exec { def foo; end } end.should raise_error(TypeError) end quarantine! do # Not clean, leaves cvars lying around to break other specs it "scopes class var accesses in the caller when called on a Fixnum" do # Fixnum can take instance vars Fixnum.class_eval "@@__tmp_instance_exec_spec = 1" (defined? @@__tmp_instance_exec_spec).should == nil @@__tmp_instance_exec_spec = 2 1.instance_exec { @@__tmp_instance_exec_spec }.should == 2 Fixnum.__send__(:remove_class_variable, :@@__tmp_instance_exec_spec) end end it "raises a TypeError when defining methods on numerics" do lambda do (1.0).instance_exec { def foo; end } end.should raise_error(TypeError) lambda do (1 << 64).instance_exec { def foo; end } end.should raise_error(TypeError) end end