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Feature: expect change
Expect the execution of a block of code to change the state of an object.
Background:
Given a file named "lib/counter.rb" with:
"""ruby
class Counter
class << self
def increment
@count ||= 0
@count += 1
end
def count
@count ||= 0
end
end
end
"""
Scenario: expect change
Given a file named "spec/example_spec.rb" with:
"""ruby
require "counter"
describe Counter, "#increment" do
it "should increment the count" do
expect { Counter.increment }.to change{Counter.count}.from(0).to(1)
end
# deliberate failure
it "should increment the count by 2" do
expect { Counter.increment }.to change{Counter.count}.by(2)
end
end
"""
When I run `rspec spec/example_spec.rb`
Then the output should contain "1 failure"
Then the output should contain "should have been changed by 2, but was changed by 1"
Scenario: expect no change
Given a file named "spec/example_spec.rb" with:
"""ruby
require "counter"
describe Counter, "#increment" do
it "should not increment the count by 1 (using not_to)" do
expect { Counter.increment }.not_to change{Counter.count}
end
it "should not increment the count by 1 (using to_not)" do
expect { Counter.increment }.to_not change{Counter.count}
end
end
"""
When I run `rspec spec/example_spec.rb`
Then the output should contain "2 failures"
Then the output should contain "should not have changed, but did change from 1 to 2"
|
