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ruby--ruby/spec/ruby/core/enumerable/one_spec.rb

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require_relative '../../spec_helper'
require_relative 'fixtures/classes'
describe "Enumerable#one?" do
before :each do
@empty = EnumerableSpecs::Empty.new
@enum = EnumerableSpecs::Numerous.new
@enum1 = EnumerableSpecs::Numerous.new(0, 1, 2, -1)
@enum2 = EnumerableSpecs::Numerous.new(nil, false, true)
end
it "always returns false on empty enumeration" do
@empty.one?.should == false
@empty.one? { true }.should == false
end
it "raises an ArgumentError when more than 1 argument is provided" do
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-> { @enum.one?(1, 2, 3) }.should raise_error(ArgumentError)
-> { [].one?(1, 2, 3) }.should raise_error(ArgumentError)
-> { {}.one?(1, 2, 3) }.should raise_error(ArgumentError)
end
it "does not hide exceptions out of #each" do
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-> {
EnumerableSpecs::ThrowingEach.new.one?
}.should raise_error(RuntimeError)
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-> {
EnumerableSpecs::ThrowingEach.new.one? { false }
}.should raise_error(RuntimeError)
end
describe "with no block" do
it "returns true if only one element evaluates to true" do
[false, nil, true].one?.should be_true
end
it "returns false if two elements evaluate to true" do
[false, :value, nil, true].one?.should be_false
end
it "returns false if all elements evaluate to false" do
[false, nil, false].one?.should be_false
end
it "gathers whole arrays as elements when each yields multiple" do
multi = EnumerableSpecs::YieldsMultiWithSingleTrue.new
multi.one?.should be_false
end
end
describe "with a block" do
it "returns true if block returns true once" do
[:a, :b, :c].one? { |s| s == :a }.should be_true
end
it "returns false if the block returns true more than once" do
[:a, :b, :c].one? { |s| s == :a || s == :b }.should be_false
end
it "returns false if the block only returns false" do
[:a, :b, :c].one? { |s| s == :d }.should be_false
end
it "does not hide exceptions out of the block" do
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-> {
@enum.one? { raise "from block" }
}.should raise_error(RuntimeError)
end
it "gathers initial args as elements when each yields multiple" do
multi = EnumerableSpecs::YieldsMulti.new
yielded = []
multi.one? { |e| yielded << e; false }.should == false
yielded.should == [1, 3, 6]
end
it "yields multiple arguments when each yields multiple" do
multi = EnumerableSpecs::YieldsMulti.new
yielded = []
multi.one? { |*args| yielded << args; false }.should == false
yielded.should == [[1, 2], [3, 4, 5], [6, 7, 8, 9]]
end
end
describe 'when given a pattern argument' do
it "calls `===` on the pattern the return value " do
pattern = EnumerableSpecs::Pattern.new { |x| x == 1 }
@enum1.one?(pattern).should == true
pattern.yielded.should == [[0], [1], [2], [-1]]
end
# may raise an exception in future versions
ruby_version_is ""..."2.6" do
it "ignores block" do
@enum2.one?(NilClass) { raise }.should == true
[1, 2, nil].one?(NilClass) { raise }.should == true
{a: 1}.one?(Array) { raise }.should == true
end
end
it "always returns false on empty enumeration" do
@empty.one?(Integer).should == false
[].one?(Integer).should == false
{}.one?(NilClass).should == false
end
it "does not hide exceptions out of #each" do
-> {
EnumerableSpecs::ThrowingEach.new.one?(Integer)
}.should raise_error(RuntimeError)
end
it "returns true if the pattern returns a truthy value only once" do
@enum2.one?(NilClass).should == true
pattern = EnumerableSpecs::Pattern.new { |x| x == 2 }
@enum1.one?(pattern).should == true
[1, 2, 42, 3].one?(pattern).should == true
pattern = EnumerableSpecs::Pattern.new { |x| x == [:b, 2] }
{a: 1, b: 2}.one?(pattern).should == true
end
it "returns false if the pattern returns a truthy value more than once" do
pattern = EnumerableSpecs::Pattern.new { |x| !x }
@enum2.one?(pattern).should == false
pattern.yielded.should == [[nil], [false]]
[1, 2, 3].one?(Integer).should == false
{a: 1, b: 2}.one?(Array).should == false
end
it "returns false if the pattern never returns a truthy value" do
pattern = EnumerableSpecs::Pattern.new { |x| nil }
@enum1.one?(pattern).should == false
pattern.yielded.should == [[0], [1], [2], [-1]]
[1, 2, 3].one?(pattern).should == false
{a: 1}.one?(pattern).should == false
end
it "does not hide exceptions out of pattern#===" do
pattern = EnumerableSpecs::Pattern.new { raise "from pattern" }
-> {
@enum.one?(pattern)
}.should raise_error(RuntimeError)
end
it "calls the pattern with gathered array when yielded with multiple arguments" do
multi = EnumerableSpecs::YieldsMulti.new
pattern = EnumerableSpecs::Pattern.new { false }
multi.one?(pattern).should == false
pattern.yielded.should == [[[1, 2]], [[3, 4, 5]], [[6, 7, 8, 9]]]
end
end
end