belong_to RSpec matcher
April 9, 2008 by Dean
I was extending acts_as_commentable and needed a good RSpec test to check the returned objects from its finder methods belonged to the correct user. For example, Comment.find_comments_by_user( :some_user ) should all belong_to :some_user. I’ll be darned if that doesn’t look like a RSpec description. Since there is no all_belong_to matcher, I wrote one.
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module ActiveRecordValidations
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class BelongTo
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def initialize(expected)
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@expected = expected
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end
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def matches?(args)
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args.all? do |target|
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@target = target
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@target.send(@expected.class.to_s.downcase) == @expected
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end
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end
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def failure_message
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"expected #{@target.inspect} to all belong to #{@expected}"
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end
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def negative_failure_message
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"expected #{@target.inspect} not to all belong to #{@expected}"
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end
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end
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def belong_to(expected)
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BelongTo.new( [expected] )
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end
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def all_belong_to(expected)
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BelongTo.new( expected )
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end
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end
The matches? method takes an array of objects and goes through them with all? checking that they have a belongs_to the expected thing. Using the example above, each comment object returned by Comment.find_comments_by_user would get tested if comment.user== @user.
–Dean
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