144 lines
4.3 KiB
Ruby
144 lines
4.3 KiB
Ruby
module Spec
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module Matchers
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#Based on patch from Wilson Bilkovich
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class Change #:nodoc:
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def initialize(receiver=nil, message=nil, &block)
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@receiver = receiver
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@message = message
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@block = block
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end
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def matches?(target, &block)
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if block
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raise MatcherError.new(<<-EOF
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block passed to should or should_not change must use {} instead of do/end
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EOF
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)
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end
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@target = target
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execute_change
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return false if @from && (@from != @before)
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return false if @to && (@to != @after)
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return (@before + @amount == @after) if @amount
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return ((@after - @before) >= @minimum) if @minimum
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return ((@after - @before) <= @maximum) if @maximum
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return @before != @after
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end
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def execute_change
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@before = @block.nil? ? @receiver.send(@message) : @block.call
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@target.call
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@after = @block.nil? ? @receiver.send(@message) : @block.call
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end
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def failure_message
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if @to
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"#{result} should have been changed to #{@to.inspect}, but is now #{@after.inspect}"
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elsif @from
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"#{result} should have initially been #{@from.inspect}, but was #{@before.inspect}"
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elsif @amount
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"#{result} should have been changed by #{@amount.inspect}, but was changed by #{actual_delta.inspect}"
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elsif @minimum
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"#{result} should have been changed by at least #{@minimum.inspect}, but was changed by #{actual_delta.inspect}"
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elsif @maximum
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"#{result} should have been changed by at most #{@maximum.inspect}, but was changed by #{actual_delta.inspect}"
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else
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"#{result} should have changed, but is still #{@before.inspect}"
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end
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end
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def result
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@message || "result"
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end
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def actual_delta
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@after - @before
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end
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def negative_failure_message
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"#{result} should not have changed, but did change from #{@before.inspect} to #{@after.inspect}"
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end
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def by(amount)
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@amount = amount
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self
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end
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def by_at_least(minimum)
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@minimum = minimum
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self
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end
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def by_at_most(maximum)
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@maximum = maximum
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self
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end
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def to(to)
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@to = to
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self
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end
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def from (from)
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@from = from
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self
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end
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end
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# :call-seq:
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# should change(receiver, message, &block)
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# should change(receiver, message, &block).by(value)
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# should change(receiver, message, &block).from(old).to(new)
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# should_not change(receiver, message, &block)
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#
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# Allows you to specify that a Proc will cause some value to change.
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#
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# == Examples
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#
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# lambda {
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# team.add_player(player)
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# }.should change(roster, :count)
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#
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# lambda {
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# team.add_player(player)
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# }.should change(roster, :count).by(1)
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#
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# lambda {
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# team.add_player(player)
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# }.should change(roster, :count).by_at_least(1)
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#
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# lambda {
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# team.add_player(player)
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# }.should change(roster, :count).by_at_most(1)
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#
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# string = "string"
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# lambda {
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# string.reverse
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# }.should change { string }.from("string").to("gnirts")
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#
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# lambda {
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# person.happy_birthday
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# }.should change(person, :birthday).from(32).to(33)
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#
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# lambda {
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# employee.develop_great_new_social_networking_app
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# }.should change(employee, :title).from("Mail Clerk").to("CEO")
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#
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# Evaluates +receiver.message+ or +block+ before and
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# after it evaluates the c object (generated by the lambdas in the examples above).
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#
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# Then compares the values before and after the +receiver.message+ and
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# evaluates the difference compared to the expected difference.
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#
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# == Warning
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# +should_not+ +change+ only supports the form with no subsequent calls to
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# +by+, +by_at_least+, +by_at_most+, +to+ or +from+.
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#
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# blocks passed to +should+ +change+ and +should_not+ +change+
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# must use the <tt>{}</tt> form (<tt>do/end</tt> is not supported)
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def change(target=nil, message=nil, &block)
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Matchers::Change.new(target, message, &block)
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end
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end
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end
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