chore(tests): improve test runner system

* Implements an extension to frktest's `lune_console_reporter` for
  displaying status of individual running test cases and suites -- with
  colors :O!
* Include mechanism for running select tests using the test runner
  script.

.lune/test.luau

@@ -4,21 +4,54 @@ local fs = require("@lune/fs")
 local process = require("@lune/process")
 
 local frktest = require("@pkg/frktest")
+local reporter = require("../tests/_reporter")
 
 -- HACK: Cast require to allow for dynamic paths in strict mode
 -- A more proper solution would be to use luau.load instead, but
 -- frktest requires its global state to be modified by test suites
-local require = require :: (path: string) -> () -> ()
-
-if process.args[1] ~= nil then
-        require("../tests/" .. process.args[1])()
-else
-        for _, test in fs.readDir("tests") do
-                require("../tests/" .. test)()
-        end
-end
+local require = require :: (
+	path: string
+) -> (
+	test: typeof(setmetatable(
+		{} :: {
+			case: (name: string, fn: () -> nil) -> (),
+			suite: (name: string, fn: () -> ()) -> (),
+		},
+		{ __index = frktest.test }
+	))
+) -> ()
+
+local allowed_tests = process.args
+for _, test in fs.readDir("tests") do
+	-- If we are given any arguments, we only run those tests, otherwise,
+	-- we run all the tests
+
+	-- So, to include only a certain set of test files, you can provide either
+	-- the full path to the test file (with or without the extension) or the test
+	-- file name
+	local withoutExt = string.sub(test, 1, -6)
+	local is_allowed = #process.args == 0
+		or table.find(allowed_tests, `tests/{test}`)
+		or table.find(allowed_tests, withoutExt)
+		or table.find(allowed_tests, `tests/{withoutExt}`)
+
+	local constructors = {
+		case = frktest.test.case,
+		suite = frktest.test.suite,
+	}
 
-frktest._reporters.lune_console_reporter.init()
-if not frktest.run() then
-        process.exit(1)
+	if not is_allowed then
+		constructors.case = frktest.test.skip.case
+		constructors.suite = frktest.test.skip.suite
+	end
+
+	-- Ignore files starting with underscores, eg: _reporter.luau
+	if string.sub(test, 1, 1) == "_" then
+		continue
+	end
+
+	require("../tests/" .. test)(setmetatable(constructors, { __index = frktest.test }))
 end
+
+reporter.init()
+process.exit(tonumber(frktest.run()))

tests/_reporter.luau

@@ -0,0 +1,55 @@
+local stdio = require("@lune/stdio")
+
+local frktest = require("@pkg/frktest")
+local Reporter = frktest._reporters.lune_console_reporter
+
+local STYLE = table.freeze({
+	suite = function(name: string)
+		return `{stdio.style("bold")}{stdio.color("purple")}SUITE{stdio.style("reset")} {name}`
+	end,
+
+	report = function(name: string, state: "run" | "success" | "error" | "skip")
+		local state_color: stdio.Color = if state == "run"
+			then "white"
+			elseif state == "success" then "green"
+			elseif state == "error" then "red"
+			elseif state == "skip" then "yellow"
+			else error("Invalid test state")
+		return `    {stdio.style("bold")}{stdio.color(state_color)}{if state == "skip" then "SKIP" else "TEST"}{stdio.style(
+			"reset"
+		)} {name}`
+	end,
+})
+
+--- Clears a the previous line, and moves to its beginning
+local function clear_last_line(): ()
+	return stdio.write("\x1b[A\x1b[K\x1b[0G\x1b[?25h")
+end
+
+local ReporterExt = {}
+function ReporterExt.init()
+	frktest.test.on_suite_enter(function(suite)
+		print(STYLE.suite(suite.name))
+	end)
+
+	frktest.test.on_suite_leave(function()
+		stdio.write("\n")
+	end)
+
+	frktest.test.on_test_enter(function(test)
+		print(STYLE.report(test.name, "run"))
+	end)
+
+	frktest.test.on_test_leave(function(test)
+		clear_last_line()
+		print(STYLE.report(test.name, if test.failed then "error" else "success"))
+	end)
+
+	frktest.test.on_test_skipped(function(test)
+		print(STYLE.report(test.name, "skip"))
+	end)
+
+	Reporter.init()
+end
+
+return setmetatable(ReporterExt, { __index = Reporter })

tests/cmp.luau

@@ -1,13 +1,12 @@
 local frktest = require("@pkg/frktest")
-local test = frktest.test
 local check = frktest.assert.check
 
 local Option = require("../luau_packages/option")
 type Option<T> = Option.Option<T>
 
 local Semver = require("../lib")
 
-return function()
+return function(test: typeof(frktest.test))
 	test.suite("Semver comparison tests", function()
 		test.case("Basic version comparisons", function()
 			local v1 = Semver.parse("1.2.3"):unwrap()

tests/parse_invalid.luau

@@ -1,10 +1,9 @@
 local frktest = require("@pkg/frktest")
-local test = frktest.test
 local check = frktest.assert.check
 
 local Semver = require("../lib")
 
-return function()
+return function(test: typeof(frktest.test))
 	test.suite("Invalid semver parsing tests", function()
 		test.case("Rejects missing components", function()
 			local res = Semver.parse("1.2")

tests/parse_valid.luau

@@ -1,13 +1,12 @@
 local frktest = require("@pkg/frktest")
-local test = frktest.test
 local check = frktest.assert.check
 
 local Option = require("../luau_packages/option")
 type Option<T> = Option.Option<T>
 
 local Semver = require("../lib")
 
-return function()
+return function(test: typeof(frktest.test))
 	test.suite("Basic tests", function()
 		test.case("Semver creates valid version objects", function()
 			local res = Semver.parse("1.2.3-beta.1")

tests/tostring.luau

@@ -1,13 +1,12 @@
 local frktest = require("@pkg/frktest")
-local test = frktest.test
 local check = frktest.assert.check
 
 local Option = require("../luau_packages/option")
 type Option<T> = Option.Option<T>
 
 local Semver = require("../lib")
 
-return function()
+return function(test: typeof(frktest.test))
 	test.suite("Stringification tests", function()
 		test.case("A version constructed with new() when stringified should match expected string", function()
 			local versionMap: { [string]: Semver.Version } = {