local multiset = require "headers.multiset"


describe("Multisets can be created", function()
	it("without errors", function()
		assert.has_no.errors(function()
			local _ = multiset.new()
		end)
	end)
end)


describe("Size of multiset", function()
	local set

	setup(function()
		set = multiset.new()
	end)

	it("can be checked with method", function()
		assert.is_not_nil(set:size())
	end)

	it("can be checked with operator", function()
		assert.is_not_nil(#set)
	end)

	it("is zero after creation", function()
		assert.are.equal(0, #set)
	end)
end)


describe("Values", function()
	randomize(false)
	local set

	setup(function()
		set = multiset.new()
	end)

	it("are not present before insertion", function()
		assert.is_false(set:has"will-be-removed")
		assert.is_false(set:has"will-stay")
		assert.is_false(set:has"never-inserted")
	end)

	it("were not tracked before insertion", function()
		assert.is_false(set:had"will-be-removed")
		assert.is_false(set:had"will-stay")
		assert.is_false(set:had"never-inserted")
	end)

	it("can be inserted", function()
		assert.has_no.errors(function()
			set:add"will-be-removed"
			set:add"will-stay"
		end)
	end)

	it("are present after insertion", function()
		assert.is_true(set:has"will-be-removed")
		assert.is_true(set:has"will-stay")
		assert.is_false(set:has"never-inserted")
	end)

	it("are tracked after insertion", function()
		assert.is_true(set:had"will-be-removed")
		assert.is_true(set:had"will-stay")
		assert.is_false(set:had"never-inserted")
	end)

	it("are counted in size", function()
		assert.are.equal(2, #set)
	end)

	it("can be removed", function()
		assert.has_no.errors(function()
			set:remove"will-be-removed"
		end)
	end)

	it("are no longer present after removal", function()
		assert.is_false(set:has"will-be-removed")
		assert.is_true(set:has"will-stay")
		assert.is_false(set:has"never-inserted")
	end)

	it("are still tracked after removal", function()
		assert.is_true(set:had"will-be-removed")
		assert.is_true(set:had"will-stay")
		assert.is_false(set:had"never-inserted")
	end)

	it("are not counted after removal", function()
		assert.are.equal(1, #set)
	end)
end)


describe("Iterator", function()
	randomize(false)
	local set

	setup(function()
		set = multiset.new()
		set:add"a"
		set:add"b"
		set:add"c"
		set:add"d"
	end)

	it("preserves order", function()
		local items = {}
		for value in set:all() do
			table.insert(items, value)
		end
		assert.are.same({"a", "b", "c", "d"}, items)
	end)

	it("does not include past values", function()
		set:remove"c"
		set:add"e"
		local items = {}
		for value in set:all() do
			table.insert(items, value)
		end
		assert.are.same({"a", "b", "d", "e"}, items)
	end)

	it("keeps the order of re-added values", function()
		set:add"c"
		local items = {}
		for value in set:all() do
			table.insert(items, value)
		end
		assert.are.same({"a", "b", "c", "d", "e"}, items)
	end)
end)


describe("Clones", function()
	randomize(false)
	local a
	local b

	setup(function()
		a = multiset.new()
		a:add"set-in-a"
	end)

	it("can be created", function()
		assert.has_no.errors(function()
			b = a:clone()
		end)
		assert.is_not_nil(b)
	end)

	it("do not interfere with their original", function()
		assert.is_true(a:has"set-in-a")
		assert.is_true(b:has"set-in-a")
		assert.is_false(a:has"set-in-b")
		assert.is_false(b:has"set-in-b")
		b:add"set-in-b"
		assert.is_false(a:has"set-in-b")
		assert.is_true(b:has"set-in-b")
	end)
end)