testlib

; This is not a script, but a macro library. To use it, copy it into
; your editor, and then ":import testlib" within your script.
; The API comes first, with implementation below.

; "testlib" - Unit testing library
; v0.9.0 2021-08-11

; Predeclaration of these functions so that the examples in the comments don't
; fail to compile.
{lua(\
  test_lib = {};\
  function test_lib.test_expr() return "" end\
  function test_lib.error_expr() return "" end\
  return "";\
)}

; Tests that "expr" is true. If it is false, the failure will be logged
; and the remaining tests will be skipped.
; Each test expression is used as part of a test runner loop. This means that
; no matter how many tests are added, the line count will not grow - it just
; adds some runtime and size to the script.
#EXPECT(expr) {lua(return test_lib.expect([===[{expr}]===]))}

; These macros evaluate to expressions that are used to form the main body
; of the test loop. See usage instructions below.
#test_loop_expr(loop_counter) {lua(return test_lib.test_expr([===[{loop_counter}]===]))}
#test_result(loop_counter) {lua(return test_lib.error_expr([===[{loop_counter}]===]))}

; An functioning test loop looks like this:
; :local int i
;
; testloop: i = i + 1
; gotoif(testloop, {test_loop_expr(i)})
; gss("<color=#fff>result</color>", {test_result(i)})

; ================= IMPLEMENTATION DETAILS BELOW =========================

{lua(\
  local tests = {};\
  test_lib.tests = tests;\
\
  local function add_quoted(acc, str)\
    acc[#acc + 1] = '"';\
    for unquoted, quotes in string.gmatch(str, '([^"]*)("*)') do\
      acc[#acc + 1] = unquoted;\
      if quotes ~= "" then\
        acc[#acc + 1] = [[" . ']] .. quotes .. [[' . "]]\
      end\
    end\
    acc[#acc + 1] = '"';\
  end\
\
  function test_lib.expect(expr)\
    tests[#tests + 1] = expr;\
    return "";\
  end\
\
  function test_lib.test_expr(loop_counter)\
    local acc = {};\
    acc[1] = "(";\
    for i = 1, #tests do\
      acc[#acc + 1] = loop_counter;\
      acc[#acc + 1] = " == " .. i .. " && (";\
      acc[#acc + 1] = tests[i];\
      acc[#acc + 1] = ")";\
      if i ~= #tests then\
        acc[#acc + 1] = " || ";\
      end\
    end\
    acc[#acc + 1] = ")";\
    return table.concat(acc);\
  end\
\
  function test_lib.error_expr(loop_counter)\
    local acc = {};\
    acc[1] = "(if(" .. loop_counter .. ' <= 0, "<color=#f44>Bad test setup, ' .. loop_counter .. ' <= 0</color>", ';\
    acc[2] = "if(" .. loop_counter .. " <= " .. #tests .. ', "<color=#f44>FAIL #" . ' .. loop_counter .. ' . ": !(" . ';\
    for i = 1, #tests - 1 do\
      acc[#acc + 1] = "if(" .. loop_counter;\
      acc[#acc + 1] = " == " .. i .. ", ";\
      add_quoted(acc, tests[i]);\
      acc[#acc + 1] = ", ";\
    end\
    add_quoted(acc, tests[#tests]);\
    for i = 1, #tests - 1 do\
      acc[#acc + 1] = ")";\
    end\
    acc[#acc + 1] = ' . ")</color>", "<color=#4f4>OK</color>")))';\
    return table.concat(acc);\
  end\
\
  return "";\
)}