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Contents
require 'rails_helper'
RSpec.describe LabTech::Percentile do
# Just keep walking, Mr. Phippen, and nobody gets hurt. ;P
def self.expect_percentile( percentile, expected_value )
specify "percentile(#{percentile}) should be #{expected_value}" do
expect( LabTech::Percentile.call(percentile, array) ).to eq( expected_value )
end
end
def self.expect_percentiles(percentiles_to_values = {})
percentiles_to_values.each do |percentile, value|
expect_percentile percentile, value
end
end
describe "examples I swiped from Wikipedia" do
# Specifically: https://en.wikipedia.org/wiki/Percentile#The_nearest-rank_method
context "for a 5-item array" do
subject(:array) { [ 15, 20, 35, 40, 50 ] }
expect_percentiles({
0 => 15,
20 => 15,
21 => 20,
40 => 20,
41 => 35,
60 => 35,
61 => 40,
80 => 40,
81 => 50,
100 => 50,
})
end
context "for a 10-item array" do
subject(:array) { [ 3, 6, 7, 8, 8, 10, 13, 15, 16, 20 ] }
expect_percentiles({
25 => 7,
50 => 8,
75 => 15,
100 => 20,
})
end
context "for an 11-item array" do
subject(:array) { [ 3, 6, 7, 8, 8, 9, 10, 13, 15, 16, 20 ] }
expect_percentiles({
25 => 7,
50 => 9,
75 => 15,
100 => 20,
})
end
end
context "for a 100-item array" do
subject(:array) { (1..100).to_a }
expect_percentiles({
0 => 1,
1 => 1,
2 => 2,
99 => 99,
100 => 100,
})
end
context "for a 1000-item array" do
subject(:array) { (1..1000).to_a }
expect_percentiles({
0 => 1,
1 => 10,
50 => 500,
99 => 990,
100 => 1000,
})
end
end
Version data entries
10 entries across 10 versions & 1 rubygems