Added file assertion

moonpie/test_helpers/busted_extensions.lua

@@ -9,4 +9,5 @@ require "moonpie.test_helpers.string_assertions"
 require "moonpie.test_helpers.number_assertions"
 require "moonpie.test_helpers.array_assertions"
 require "moonpie.test_helpers.mock_love"
-require "moonpie.test_helpers.spy_helpers"
+require "moonpie.test_helpers.spy_helpers"
+require "moonpie.test_helpers.file_assertions"

moonpie/test_helpers/file_assertations_spec.lua

@@ -0,0 +1,12 @@
+-- Copyright (c) 2020 Trevor Redfern
+--
+-- This software is released under the MIT License.
+-- https://opensource.org/licenses/MIT
+
+describe("moonpie.test_helpers.file_assertions", function()
+  it("can assert that a file exists", function()
+    assert.file_exists("moonpie/test_helpers/file_assertions.lua")
+    assert.not_file_exists("some/totally_random/file/name.foo")
+  end)
+
+end)

moonpie/test_helpers/file_assertions.lua

@@ -0,0 +1,21 @@
+-- Copyright (c) 2020 Trevor Redfern
+--
+-- This software is released under the MIT License.
+-- https://opensource.org/licenses/MIT
+
+
+local assert = require("luassert")
+local say = require("say")
+
+local function file_exists(state, arguments)
+  local path = arguments[1]
+  local f = io.open(path, "r")
+  local result = f ~= nil
+  if f then f:close() end
+  return result
+end
+
+
+say:set("assertion.file_exists.positive", "File %s does not exist.")
+say:set("assertion.file_exists.negative", "File %s exists and should not.")
+assert:register("assertion", "file_exists", file_exists, "assertion.file_exists.positive", "assertion.file_exists.negative")