The Four-Phase Test is a testing pattern, applicable to all programming languages and unit tests (not so much integration tests).
It takes the following general form:
test do
setup
exercise
verify
teardown
end
There are four distinct phases of the test. They are executed sequentially.
setup
During setup, the system under test (usually a class, object, or method) is set up.
user = User.new(password: 'password')
exercise
During exercise, the system under test is executed.
user.save
verify
During verification, the result of the exercise is verified against the developer’s expectations.
user.encrypted_password.should_not be_nil
teardown
During teardown, the system under test is reset to its pre-setup state.
This is usually handled implicitly by the language (releasing memory) or test framework (running inside a database transaction).
all together
The four phases are wrapped into a named test to be referenced individually.
Our style guide advises we “Separate setup, exercise, verification, and teardown phases with newlines.”
it 'encrypts the password' do
user = User.new(password: 'password')
user.save
user.encrypted_password.should_not be_nil
end
Go forth and test in phases.
