spec/util_throttle_spec.lua

   1
   2
   3 -- Mock util.time
   4 local now = 0; -- wibbly-wobbly... timey-wimey... stuff
   5 local function later(n)
   6         now = now + n; -- time passes at a different rate
   7 end
   8 package.loaded["util.time"] = {
   9         now = function() return now; end
  10 }
  11
  12
  13 local throttle = require "util.throttle";
  14
  15 describe("util.throttle", function()
  16         describe("#create()", function()
  17                 it("should be created with correct values", function()
  18                         now = 5;
  19                         local a = throttle.create(3, 10);
  20                         assert.same(a, { balance = 3, max = 3, rate = 0.3, t = 5 });
  21
  22                         local a = throttle.create(3, 5);
  23                         assert.same(a, { balance = 3, max = 3, rate = 0.6, t = 5 });
  24
  25                         local a = throttle.create(1, 1);
  26                         assert.same(a, { balance = 1, max = 1, rate = 1, t = 5 });
  27
  28                         local a = throttle.create(10, 10);
  29                         assert.same(a, { balance = 10, max = 10, rate = 1, t = 5 });
  30
  31                         local a = throttle.create(10, 1);
  32                         assert.same(a, { balance = 10, max = 10, rate = 10, t = 5 });
  33                 end);
  34         end);
  35
  36         describe("#update()", function()
  37                 it("does nothing when no time has passed, even if balance is not full", function()
  38                         now = 5;
  39                         local a = throttle.create(10, 10);
  40                         for i=1,5 do
  41                                 a:update();
  42                                 assert.same(a, { balance = 10, max = 10, rate = 1, t = 5 });
  43                         end
  44                         a.balance = 0;
  45                         for i=1,5 do
  46                                 a:update();
  47                                 assert.same(a, { balance = 0, max = 10, rate = 1, t = 5 });
  48                         end
  49                 end);
  50                 it("updates only time when time passes but balance is full", function()
  51                         now = 5;
  52                         local a = throttle.create(10, 10);
  53                         for i=1,5 do
  54                                 later(5);
  55                                 a:update();
  56                                 assert.same(a, { balance = 10, max = 10, rate = 1, t = 5 + i*5 });
  57                         end
  58                 end);
  59                 it("updates balance when balance has room to grow as time passes", function()
  60                         now = 5;
  61                         local a = throttle.create(10, 10);
  62                         a.balance = 0;
  63                         assert.same(a, { balance = 0, max = 10, rate = 1, t = 5 });
  64
  65                         later(1);
  66                         a:update();
  67                         assert.same(a, { balance = 1, max = 10, rate = 1, t = 6 });
  68
  69                         later(3);
  70                         a:update();
  71                         assert.same(a, { balance = 4, max = 10, rate = 1, t = 9 });
  72
  73                         later(10);
  74                         a:update();
  75                         assert.same(a, { balance = 10, max = 10, rate = 1, t = 19 });
  76                 end);
  77                 it("handles 10 x 0.1s updates the same as 1 x 1s update ", function()
  78                         now = 5;
  79                         local a = throttle.create(1, 1);
  80
  81                         a.balance = 0;
  82                         later(1);
  83                         a:update();
  84                         assert.same(a, { balance = 1, max = 1, rate = 1, t = now });
  85
  86                         a.balance = 0;
  87                         for i=1,10 do
  88                                 later(0.1);
  89                                 a:update();
  90                         end
  91                         assert(math.abs(a.balance - 1) < 0.0001); -- incremental updates cause rounding errors
  92                 end);
  93         end);
  94
  95         -- describe("po")
  96
  97         describe("#poll()", function()
  98                 it("should only allow successful polls until cost is hit", function()
  99                         now = 5;
 100
 101                         local a = throttle.create(3, 10);
 102                         assert.same(a, { balance = 3, max = 3, rate = 0.3, t = 5 });
 103
 104                         assert.is_true(a:poll(1));  -- 3 -> 2
 105                         assert.same(a, { balance = 2, max = 3, rate = 0.3, t = 5 });
 106
 107                         assert.is_true(a:poll(2));  -- 2 -> 1
 108                         assert.same(a, { balance = 0, max = 3, rate = 0.3, t = 5 });
 109
 110                         assert.is_false(a:poll(1)); -- MEEP, out of credits!
 111                         assert.is_false(a:poll(1)); -- MEEP, out of credits!
 112                         assert.same(a, { balance = 0, max = 3, rate = 0.3, t = 5 });
 113                 end);
 114
 115                 it("should not allow polls more than the cost", function()
 116                         now = 0;
 117
 118                         local a = throttle.create(10, 10);
 119                         assert.same(a, { balance = 10, max = 10, rate = 1, t = 0 });
 120
 121                         assert.is_false(a:poll(11));
 122                         assert.same(a, { balance = 10, max = 10, rate = 1, t = 0 });
 123
 124                         assert.is_true(a:poll(6));
 125                         assert.same(a, { balance = 4, max = 10, rate = 1, t = 0 });
 126
 127                         assert.is_false(a:poll(5));
 128                         assert.same(a, { balance = 4, max = 10, rate = 1, t = 0 });
 129
 130                         -- fractional
 131                         assert.is_true(a:poll(3.5));
 132                         assert.same(a, { balance = 0.5, max = 10, rate = 1, t = 0 });
 133
 134                         assert.is_true(a:poll(0.25));
 135                         assert.same(a, { balance = 0.25, max = 10, rate = 1, t = 0 });
 136
 137                         assert.is_false(a:poll(0.3));
 138                         assert.same(a, { balance = 0.25, max = 10, rate = 1, t = 0 });
 139
 140                         assert.is_true(a:poll(0.25));
 141                         assert.same(a, { balance = 0, max = 10, rate = 1, t = 0 });
 142
 143                         assert.is_false(a:poll(0.1));
 144                         assert.same(a, { balance = 0, max = 10, rate = 1, t = 0 });
 145
 146                         assert.is_true(a:poll(0));
 147                         assert.same(a, { balance = 0, max = 10, rate = 1, t = 0 });
 148                 end);
 149         end);
 150 end);