102 lines
2.1 KiB
Ruby
102 lines
2.1 KiB
Ruby
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require 'spec_helper'
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describe 'null object impersonating another type' do
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class Point
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def x
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23
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end
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def y
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42
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end
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end
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subject(:null) { impersonation_class.new }
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let(:impersonation_class) do
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Naught.build do |b|
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b.impersonate Point
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end
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end
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it 'matches the impersonated type' do
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expect(null).to be_a Point
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end
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it 'responds to methods from the impersonated type' do
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expect(null.x).to be_nil
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expect(null.y).to be_nil
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end
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it 'does not respond to unknown methods' do
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expect { null.foo }.to raise_error(NoMethodError)
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end
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end
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describe 'traceable null object' do
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subject(:trace_null) do
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null_object_and_line.first
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end
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let(:null_object_and_line) do
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obj, line = trace_null_class.new, __LINE__
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[obj, line]
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end
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let(:instantiation_line) { null_object_and_line.last }
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let(:trace_null_class) do
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Naught.build do |b|
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b.traceable
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end
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end
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it 'remembers the file it was instantiated from' do
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expect(trace_null.__file__).to eq(__FILE__)
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end
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it 'remembers the line it was instantiated from' do
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expect(trace_null.__line__).to eq(instantiation_line)
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end
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def make_null
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trace_null_class.get(:caller => caller(1))
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end
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it 'can accept custom backtrace info' do
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obj, line = make_null, __LINE__
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expect(obj.__line__).to eq(line)
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end
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end
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describe 'customized null object' do
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subject(:custom_null) { custom_null_class.new }
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let(:custom_null_class) do
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Naught.build do |b|
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b.define_explicit_conversions
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def to_path
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'/dev/null'
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end
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def to_s
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'NOTHING TO SEE HERE'
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end
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end
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end
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it 'responds to custom-defined methods' do
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expect(custom_null.to_path).to eq('/dev/null')
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end
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it 'allows generated methods to be overridden' do
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expect(custom_null.to_s).to eq('NOTHING TO SEE HERE')
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end
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end
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TestNull = Naught.build
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describe 'a named null object class' do
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it 'has named ancestor modules', :pending => rubinius? do
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expect(TestNull.ancestors[0..2].collect(&:name)).to eq([
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'TestNull',
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'TestNull::Customizations',
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'TestNull::GeneratedMethods'
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])
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end
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end
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