dodb.cr/spec/test-fifo.cr

require "spec"
require "./db-cars.cr"

describe "FIFO" do
	it "add and remove values" do
		fifo = FIFO(Int32).new 3 # Only 3 allowed entries.
		(fifo << 1).should be_nil # there is still room in the stack
		(fifo << 2).should be_nil # there is still room in the stack
		(fifo << 3).should be_nil # last entry without exceeding the allowed size
		(fifo << 4).should eq 1   # -> 1 (least recently used data)
		(fifo << 4).should be_nil # -> nil (already in the stack)
		(fifo << 2).should be_nil # -> nil (already in the stack)
		(fifo << 5).should eq 3   # -> 3 (least recently used data)
		fifo.data.should eq([5, 2, 4] of Int32)
	end
end

describe "SPECDB::FIFO" do
	it "basics, 3 values" do
		car0 = Car.new "Corvet-0", "red", [] of String
		car1 = Car.new "Corvet-1", "red", [] of String
		car2 = Car.new "Corvet-2", "red", [] of String
		car3 = Car.new "Corvet-3", "red", [] of String

		db = SPECDB::FIFO(Car).new "", 3

		db.data.keys.sort.should eq([] of Int32)

		db << car0
		db.data.keys.sort.should eq([0] of Int32)

		db << car1
		db.data.keys.sort.should eq([0, 1] of Int32)

		db << car2
		db.data.keys.sort.should eq([0, 1, 2] of Int32)
		db[0] # Let's use the first value, it shouldn't be the one to be dropped.

		db << car3
		db.data.keys.sort.should eq([0, 2, 3] of Int32)
	end
end