Run all lua examples in docs as doctests

tests/main.lua

@@ -12,6 +12,7 @@ local color = {
   reset = "\x1b[0m",
   pass = "\x1b[32;1m", -- green
   fail = "\x1b[31;1m", -- red
+  faint = "\x1b[2;39;49m", -- faint
 }
 
 local icon = {
@@ -24,6 +25,12 @@ local function style(name, s)
   return ("%s%s%s"):format(color[name], s, color.reset)
 end
 
+local function rjust(s, w)
+  if w == nil then w = 12 end
+  if #s >= w then return s end
+  return (" "):rep(w - #s) .. s
+end
+
 local function create_test(name, f, group)
   local test = { type = "test", name = name or "", group = group, state = "pending", f = f }
   local fenv = setmetatable({}, { __index = global, __newindex = global })
@@ -67,13 +74,13 @@ local function trace(msg)
 end
 
 local function run_test(test)
-  local ok, res = xpcall(test.f, trace, test)
+  local ok, trace = xpcall(test.f, trace, test)
   if ok then
     test.state = "pass"
-    print("", ("%s %s"):format(style("pass", "PASS"), name_test(test)))
+    print(("%s %s"):format(style("pass", rjust("PASS")), name_test(test)))
   else
     test.state = "fail"
-    print("", ("%s %s\n\n%s\n"):format(style("fail", "FAIL"), name_test(test), res))
+    print(("%s %s\n\n%s\n"):format(style("fail", rjust("!!! FAIL")), name_test(test), trace))
   end
   collectgarbage() -- gc after each test to test destructors
   return test
@@ -118,28 +125,24 @@ local function main(item)
     end
   end
   local elapsed = time:elapsed_secs()
-  local code = 1
+  local retcode
   if fail == 0 then
-    print("", style("pass", ("%s %d tests passed"):format(icon.check, pass)))
-    code = 0
+    print(style("pass", ("\t%s %d tests passed"):format(icon.check, pass)))
+    retcode = 0
   else
     print(
-      "",
-      ("%s, %s"):format(
+      ("\t%s, %s"):format(
         style("pass", ("%s %d tests passed"):format(icon.check, pass)),
         style("fail", ("%s %d tests failed"):format(icon.cross, fail))
       )
     )
+    retcode = 1
   end
-  if elapsed < 1000 then
-    print("", ("%s completed in %.2f ms"):format(icon.chevron, elapsed * 1000))
-  else
-    print("", ("%s completed in %.2f s"):format(icon.chevron, elapsed))
-  end
+  print(style("faint", ("\t%s completed in %.2fs"):format(icon.chevron, elapsed)))
   cx = nil
   collectgarbage()
-  check_refs()
-  return code -- report error to cargo
+  check_refs() -- check that all refs were properly unref'ed in destructors
+  return retcode -- report error to cargo
 end
 
 return main(create_group("", function()
@@ -152,6 +155,34 @@ return main(create_group("", function()
     end
   end
 
+  local function include_doctest(path, pat)
+    for entry in fs.glob_dir(path, pat) do
+      local line, doctest = 0, nil
+      for s in fs.read(entry:path()):gmatch("([^\n]*)\n?") do
+        line = line + 1
+        local prefix = s:match("^%s*///")
+        s = prefix and s:sub(#prefix + 1)
+        if s and not s:match("^%s*```%s*$") then
+          if s:match("^%s*```lua$") then
+            doctest = { line = line, col = #prefix + 2 }
+          elseif doctest then
+            table.insert(doctest, (" "):rep(#prefix) .. s)
+          end
+        else
+          if doctest then
+            local name = ("%s:%d:%d"):format(entry:path(), doctest.line, doctest.col)
+            local f, err = loadstring(table.concat(doctest, "\n"), "@" .. name)
+            if not f then error(err) end
+            test(("%s %s"):format(name, style("faint", "(doctest)")), f)
+          end
+          doctest = nil
+        end
+      end
+    end
+  end
+
   include("tests", "**/*.lua")
   include("crates", "*/tests/**/*.lua")
+  include_doctest("src", "**/*.rs")
+  include_doctest("crates", "*/src/**/*.rs")
 end))