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require File.expand_path('../../spec_helper', __FILE__)
describe "The throw keyword" do
it "abandons processing" do
i = 0
catch(:done) do
loop do
i += 1
throw :done if i > 4
end
i += 1
end
i.should == 5
end
it "supports a second parameter" do
msg = catch(:exit) do
throw :exit,:msg
end
msg.should == :msg
end
it "uses nil as a default second parameter" do
msg = catch(:exit) do
throw :exit
end
msg.should == nil
end
it "clears the current exception" do
catch :exit do
begin
raise "exception"
rescue
throw :exit
end
end
$!.should be_nil
end
it "allows any object as its argument" do
catch(1) { throw 1, 2 }.should == 2
o = Object.new
catch(o) { throw o, o }.should == o
end
it "does not convert strings to a symbol" do
lambda { catch(:exit) { throw "exit" } }.should raise_error(ArgumentError)
end
it "unwinds stack from within a method" do
def throw_method(handler, val)
throw handler, val
end
catch(:exit) do
throw_method(:exit, 5)
end.should == 5
end
it "unwinds stack from within a lambda" do
c = lambda { throw :foo, :msg }
catch(:foo) { c.call }.should == :msg
end
it "raises an ArgumentError if outside of scope of a matching catch" do
lambda { throw :test, 5 }.should raise_error(ArgumentError)
lambda { catch(:different) { throw :test, 5 } }.should raise_error(ArgumentError)
end
it "raises an ArgumentError if used to exit a thread" do
lambda {
catch(:what) do
Thread.new {
throw :what
}.join
end
}.should raise_error(ArgumentError)
end
end
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