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require 'test_helper'
require 'rantly/shrinks'
require 'rantly/minitest_extensions'
module RantlyTest
end
module RantlyTest::Shrinkers
end
describe Integer do
it 'not be able to shrink 0 integer' do
assert !0.shrinkable?
end
it 'shrink positive integers to something less than itself' do
assert(3.shrink < 3)
assert(2.shrink < 2)
assert_equal(0, 1.shrink)
end
it 'shrink negative integers to something larger than itself' do
assert(-3.shrink > -3)
assert(-2.shrink > -2)
assert_equal(0, -1.shrink)
end
it 'shrink 0 to itself' do
# hmm. should this be undefined?
assert_equal 0.shrink, 0
end
end
describe String do
it 'not be able to shrink empty string' do
assert !''.shrinkable?
end
it 'shrink a string one char shorter' do
property_of do
sized(10) { string }
end.check do |str|
assert_equal 9, str.shrink.length
end
end
end
describe Tuple do
it 'not be able to shrink empty tuple' do
assert !Tuple.new([]).shrinkable?
end
it 'shrink tuple by trying to shrink the last shrinkable element available' do
assert_equal [1, 0], Tuple.new([1, 1]).shrink.array
assert_equal [1, 0, 0], Tuple.new([1, 1, 0]).shrink.array
end
it 'do not remove element from array when no element is shrinkable' do
property_of do
n = integer(1..10)
a = Tuple.new(Array.new(n, 0))
[n, a]
end.check do |n, a|
assert_equal n, a.shrink.length
end
end
end
describe Hash do
it 'not be able to shrink empty hash' do
assert !{}.shrinkable?
end
it 'shrink a value if one of the values is shrinkable' do
assert_equal({ foo: 0, bar: 0 }, { foo: 1, bar: 0 }.shrink)
assert_equal({ foo: 0, bar: 0 }, { foo: 0, bar: 1 }.shrink)
end
it 'shrink by deleting an element in it if none of the values is shrinkable' do
assert_equal({}, { foo: 0 }.shrink)
end
end
describe 'Shrinker Test' do
it 'shrink data to smallest value that fails assertion' do
print "\n### TESTING A FAILING CASE, do not get scared"
# We try to generate an array of 10 elements, filled with ones.
# The property we try to test is that non of the element is
# larger than 1, and the array's length is less than 4.
test = property_of do
a = Deflating.new(Array.new(10, 1))
i = Random.rand(a.length)
a[i] = 1
a
end
assert_raises MiniTest::Assertion do
test.check do |a|
assert(a.array.none?(&:positive?) && a.length < 4, 'contains 1')
end
end
assert_equal [1], test.shrunk_failed_data.array
end
end
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