"Assertion" Standard Library

[well-in-that-case]

Adds the following assertions:

• isnil
• istrue
• isfalse
• falsy
• truthy
• notnil
• equal
  • Supports tables.
• nequal
  • Supports tables.
• lessthan
• lessthaneq
• greaterthan
• greaterthaneq
• noerror
• haserror
• containserror
  • Checks for a substring inside of an error message.
• type
  • Supports vararg.

The main purpose of the library is descriptive errors which allow one execution pass to make the issue obvious.

pluto: test.pluto:2 -> Assertion Error: (assert.equal)
        Intended Value: string(5) "*****"
        Received Value: string(4) "****"

pluto: test.pluto:2 -> Assertion Error: (assert.equal)
        Intended Value: { [1] = string(2) "my", [2] = string(5) "split", [3] = string(6) "string", }
        Received Value: { [1] = string(2) "my", [2] = string(5) "split", [3] = string(5) "thing", }

pluto: test.pluto:2 -> Assertion Error: (assert.containserror)
        Absent String: length
        Error Message: argument 'count' for string.duplicate must be larger than zero

pluto: test.pluto:2 -> Assertion Error: (assert.type, argument #5)
        Intended Type: number
        Received Value: string(5) "hello"

Name shadowing is not a worry because __call redirects to a custom reimplementation of _G.assert

local assert = require("assert")
assert(false, "uh oh")

pluto: test.pluto:2 -> Assertion Error: (assert.assert)
         uh oh

To-Do:

• deepCompare always fails when the first table is empty.
  • The cause is obvious, only t1 gets iterated. Considering adding a table.compare first.
• A test suite that allows us to easily observe the error messages of every assert.

Resolving the file:line of the original assertion call is a little awkward since we pick the first source file we find. We always have the correct information in the traceback, problem is figuring out which file it may be.