util.dbuffer: Add efficient shortcuts for discard() in certain cases
If the buffer is already empty, nothing to do. If we're throwing away the
whole buffer, we can just empty it and avoid read_chunk() (which in turn
may collapse()). These shortcuts are much more efficient.
local random = require "util.random";
describe("util.random", function()
describe("#bytes()", function()
it("should return a string", function()
assert.is_string(random.bytes(16));
end);
it("should return the requested number of bytes", function()
-- Makes no attempt at testing how random the bytes are,
-- just that it returns the number of bytes requested
for i = 1, 20 do
assert.are.equal(2^i, #random.bytes(2^i));
end
end);
end);
end);