From 8aecd63378f6dc3aeafe71d91212f613aa0bb829 Mon Sep 17 00:00:00 2001 From: Kjetil Torgrim Homme Date: Tue, 8 Dec 2015 14:59:12 +0100 Subject: (#2886) seeded_rand: new function seeded_rand is needed for repeatable randomness across nodes in a cluster --- spec/functions/seeded_rand_spec.rb | 53 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 spec/functions/seeded_rand_spec.rb (limited to 'spec/functions/seeded_rand_spec.rb') diff --git a/spec/functions/seeded_rand_spec.rb b/spec/functions/seeded_rand_spec.rb new file mode 100644 index 0000000..38e134e --- /dev/null +++ b/spec/functions/seeded_rand_spec.rb @@ -0,0 +1,53 @@ +require 'spec_helper' + +describe 'seeded_rand' do + it { is_expected.not_to eq(nil) } + it { is_expected.to run.with_params().and_raise_error(ArgumentError, /wrong number of arguments/i) } + it { is_expected.to run.with_params(1).and_raise_error(ArgumentError, /wrong number of arguments/i) } + it { is_expected.to run.with_params(0, '').and_raise_error(ArgumentError, /first argument must be a positive integer/) } + it { is_expected.to run.with_params(1.5, '').and_raise_error(ArgumentError, /first argument must be a positive integer/) } + it { is_expected.to run.with_params(-10, '').and_raise_error(ArgumentError, /first argument must be a positive integer/) } + it { is_expected.to run.with_params("-10", '').and_raise_error(ArgumentError, /first argument must be a positive integer/) } + it { is_expected.to run.with_params("string", '').and_raise_error(ArgumentError, /first argument must be a positive integer/) } + it { is_expected.to run.with_params([], '').and_raise_error(ArgumentError, /first argument must be a positive integer/) } + it { is_expected.to run.with_params({}, '').and_raise_error(ArgumentError, /first argument must be a positive integer/) } + it { is_expected.to run.with_params(1, 1).and_raise_error(ArgumentError, /second argument must be a string/) } + it { is_expected.to run.with_params(1, []).and_raise_error(ArgumentError, /second argument must be a string/) } + it { is_expected.to run.with_params(1, {}).and_raise_error(ArgumentError, /second argument must be a string/) } + + it "provides a random number strictly less than the given max" do + expect(seeded_rand(3, 'seed')).to satisfy {|n| n.to_i < 3 } + end + + it "provides a random number greater or equal to zero" do + expect(seeded_rand(3, 'seed')).to satisfy {|n| n.to_i >= 0 } + end + + it "provides the same 'random' value on subsequent calls for the same host" do + expect(seeded_rand(10, 'seed')).to eql(seeded_rand(10, 'seed')) + end + + it "allows seed to control the random value on a single host" do + first_random = seeded_rand(1000, 'seed1') + second_different_random = seeded_rand(1000, 'seed2') + + expect(first_random).not_to eql(second_different_random) + end + + it "should not return different values for different hosts" do + val1 = seeded_rand(1000, 'foo', :host => "first.host.com") + val2 = seeded_rand(1000, 'foo', :host => "second.host.com") + + expect(val1).to eql(val2) + end + + def seeded_rand(max, seed, args = {}) + host = args[:host] || '127.0.0.1' + + # workaround not being able to use let(:facts) because some tests need + # multiple different hostnames in one context + scope.stubs(:lookupvar).with("::fqdn", {}).returns(host) + + scope.function_seeded_rand([max, seed]) + end +end -- cgit v1.2.3