55 lines
1.3 KiB
Ruby
55 lines
1.3 KiB
Ruby
require File.expand_path(File.dirname(__FILE__) + '/edgecase')
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class AboutToStr < EdgeCase::Koan
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class CanNotBeTreatedAsString
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def to_s
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"non-string-like"
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end
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end
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def test_to_s_returns_a_string_representation
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not_like_a_string = CanNotBeTreatedAsString.new
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assert_equal __, not_like_a_string.to_s
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end
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def test_normally_objects_cannot_be_used_where_strings_are_expected
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assert_raise(___) do
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File.exist?(CanNotBeTreatedAsString.new)
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end
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end
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# ------------------------------------------------------------------
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class CanBeTreatedAsString
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def to_s
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"string-like"
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end
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def to_str
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to_s
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end
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end
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def test_to_str_also_returns_a_string_representation
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like_a_string = CanBeTreatedAsString.new
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assert_equal __, like_a_string.to_str
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end
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def test_to_str_allows_objects_to_be_treated_as_strings
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assert_equal __, File.exist?(CanBeTreatedAsString.new)
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end
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# ------------------------------------------------------------------
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def acts_like_a_string?(string)
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string = string.to_str if string.respond_to?(:to_str)
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string.is_a?(String)
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end
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def test_user_defined_code_can_check_for_to_str
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assert_equal __, acts_like_a_string?(CanNotBeTreatedAsString.new)
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assert_equal __, acts_like_a_string?(CanBeTreatedAsString.new)
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end
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end
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