Lua Busted table contains assertion

assert_contains.lua

local s = require("say")

local function contains(container, contained)
  if container == contained then return true end
  local t1,t2 = type(container), type(contained)
  if t1 ~= t2 then return false end

  if t1 == 'table' then
    for k,v in pairs(contained) do
      if not contains(container[k], v) then return false end
    end
    return true
  end
  return false
end

local function contains_for_luassert(state, arguments)
  return contains(arguments[1], arguments[2])
end

s:set("assertion.contains.positive", "Expected %s\n to contain \n%s")
s:set("assertion.contains.negative", "Expected %s\n to NOT contain \n%s")

assert:register("assertion", "contains", contains_for_luassert, "assertion.contains.positive", "assertion.contains.negative")

assert_contains_spec.lua

require 'assert_contains'

describe("contains", function()
  it("works in the basic case", function()
    assert.contains({a=1,b=2,c=3}, {a=1})
    assert.contains({a=1,b=2,c=3}, {a=1, c=3})
    assert.not_contains({a=1,b=2,c=3}, {c=5})
    assert.not_contains({a=1,b=2,c=3}, {x=5})
    assert.not_contains({a=1,b=2,c=3}, {a=1, b=5, c=3})
  end)
  it("works in the complex case", function()
    assert.contains({a={b=1}, c=1}, {a={b=1}})
  end)
end)