StdioTrap
StdioTrap lets you capture stdout, stderr at runtime, e.g. for inspection inside a unit-test. It can also fake stdin.
Example (rspec)
require 'stdiotrap'
describe StdioTrap do
describe 'Inline usage' do
it "captures stdout and stderr" do
trapped = StdioTrap.capture {
puts "Hello world!"
$stderr.puts "Hello other world!"
}
trapped[:stdout].should == "Hello world!\n"
trapped[:stderr].should == "Hello other world!\n"
end
end
describe 'Common rspec usage' do
before :each do
StdioTrap.trap!
end
after :each do
StdioTrap.release!
end
it "captures stdout and stderr" do
puts "Hello world!"
$stderr.puts "Hello other world!"
StdioTrap.stdout.should == "Hello world!\n"
StdioTrap.stderr.should == "Hello other world!\n"
end
end
end
For more usage examples please refer to the spec suite.
Credits
StdioTrap is based on this code snippet (bottom of page) by Ng Tze Yang