Tests: Move Userland/Utilities/test-js to Tests/LibJS

1 files changed, 750 insertions, 0 deletions

diff --git a/Tests/LibJS/test-js.cpp b/Tests/LibJS/test-js.cpp
new file mode 100644
index 0000000000..94a265520a
--- /dev/null
+++ b/Tests/LibJS/test-js.cpp
@@ -0,0 +1,750 @@
+/*
+ * Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
+ * Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/ByteBuffer.h>
+#include <AK/JsonObject.h>
+#include <AK/JsonValue.h>
+#include <AK/LexicalPath.h>
+#include <AK/QuickSort.h>
+#include <LibCore/ArgsParser.h>
+#include <LibCore/DirIterator.h>
+#include <LibCore/File.h>
+#include <LibJS/Interpreter.h>
+#include <LibJS/Lexer.h>
+#include <LibJS/Parser.h>
+#include <LibJS/Runtime/Array.h>
+#include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/JSONObject.h>
+#include <LibTest/Results.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#define TOP_LEVEL_TEST_NAME "__$$TOP_LEVEL$$__"
+
+RefPtr<JS::VM> vm;
+
+static bool collect_on_every_allocation = false;
+static String currently_running_test;
+
+struct ParserError {
+    JS::Parser::Error error;
+    String hint;
+};
+
+struct JSFileResult {
+    String name;
+    Optional<ParserError> error {};
+    double time_taken { 0 };
+    // A failed test takes precedence over a skipped test, which both have
+    // precedence over a passed test
+    Test::Result most_severe_test_result { Test::Result::Pass };
+    Vector<Test::Suite> suites {};
+    Vector<String> logged_messages {};
+};
+
+class TestRunnerGlobalObject final : public JS::GlobalObject {
+    JS_OBJECT(TestRunnerGlobalObject, JS::GlobalObject);
+
+public:
+    TestRunnerGlobalObject();
+    virtual ~TestRunnerGlobalObject() override;
+
+    virtual void initialize_global_object() override;
+
+private:
+    JS_DECLARE_NATIVE_FUNCTION(is_strict_mode);
+    JS_DECLARE_NATIVE_FUNCTION(can_parse_source);
+    JS_DECLARE_NATIVE_FUNCTION(run_queued_promise_jobs);
+};
+
+class TestRunner {
+public:
+    static TestRunner* the()
+    {
+        return s_the;
+    }
+
+    TestRunner(String test_root, bool print_times, bool print_progress)
+        : m_test_root(move(test_root))
+        , m_print_times(print_times)
+        , m_print_progress(print_progress)
+    {
+        VERIFY(!s_the);
+        s_the = this;
+    }
+
+    virtual ~TestRunner() = default;
+
+    void run();
+
+    const Test::Counts& counts() const { return m_counts; }
+
+    bool is_printing_progress() const { return m_print_progress; }
+
+protected:
+    static TestRunner* s_the;
+
+    virtual Vector<String> get_test_paths() const;
+    virtual JSFileResult run_file_test(const String& test_path);
+    void print_file_result(const JSFileResult& file_result) const;
+    void print_test_results() const;
+
+    String m_test_root;
+    bool m_print_times;
+    bool m_print_progress;
+
+    double m_total_elapsed_time_in_ms { 0 };
+    Test::Counts m_counts;
+
+    RefPtr<JS::Program> m_test_program;
+};
+
+TestRunner* TestRunner::s_the = nullptr;
+
+TestRunnerGlobalObject::TestRunnerGlobalObject()
+{
+}
+
+TestRunnerGlobalObject::~TestRunnerGlobalObject()
+{
+}
+
+void TestRunnerGlobalObject::initialize_global_object()
+{
+    Base::initialize_global_object();
+    static FlyString global_property_name { "global" };
+    static FlyString is_strict_mode_property_name { "isStrictMode" };
+    static FlyString can_parse_source_property_name { "canParseSource" };
+    static FlyString run_queued_promise_jobs_property_name { "runQueuedPromiseJobs" };
+    define_property(global_property_name, this, JS::Attribute::Enumerable);
+    define_native_function(is_strict_mode_property_name, is_strict_mode);
+    define_native_function(can_parse_source_property_name, can_parse_source);
+    define_native_function(run_queued_promise_jobs_property_name, run_queued_promise_jobs);
+}
+
+JS_DEFINE_NATIVE_FUNCTION(TestRunnerGlobalObject::is_strict_mode)
+{
+    return JS::Value(vm.in_strict_mode());
+}
+
+JS_DEFINE_NATIVE_FUNCTION(TestRunnerGlobalObject::can_parse_source)
+{
+    auto source = vm.argument(0).to_string(global_object);
+    if (vm.exception())
+        return {};
+    auto parser = JS::Parser(JS::Lexer(source));
+    parser.parse_program();
+    return JS::Value(!parser.has_errors());
+}
+
+JS_DEFINE_NATIVE_FUNCTION(TestRunnerGlobalObject::run_queued_promise_jobs)
+{
+    vm.run_queued_promise_jobs();
+    return JS::js_undefined();
+}
+
+static void cleanup_and_exit()
+{
+    // Clear the taskbar progress.
+    if (TestRunner::the() && TestRunner::the()->is_printing_progress())
+        warn("\033]9;-1;\033\\");
+    exit(1);
+}
+
+static void handle_sigabrt(int)
+{
+    dbgln("test-js: SIGABRT received, cleaning up.");
+    cleanup_and_exit();
+}
+
+static double get_time_in_ms()
+{
+    struct timeval tv1;
+    auto return_code = gettimeofday(&tv1, nullptr);
+    VERIFY(return_code >= 0);
+    return static_cast<double>(tv1.tv_sec) * 1000.0 + static_cast<double>(tv1.tv_usec) / 1000.0;
+}
+
+template<typename Callback>
+static void iterate_directory_recursively(const String& directory_path, Callback callback)
+{
+    Core::DirIterator directory_iterator(directory_path, Core::DirIterator::Flags::SkipDots);
+
+    while (directory_iterator.has_next()) {
+        auto file_path = directory_iterator.next_full_path();
+        if (Core::File::is_directory(file_path)) {
+            iterate_directory_recursively(file_path, callback);
+        } else {
+            callback(move(file_path));
+        }
+    }
+}
+
+Vector<String> TestRunner::get_test_paths() const
+{
+    Vector<String> paths;
+    iterate_directory_recursively(m_test_root, [&](const String& file_path) {
+        if (!file_path.ends_with("test-common.js"))
+            paths.append(file_path);
+    });
+    quick_sort(paths);
+    return paths;
+}
+
+void TestRunner::run()
+{
+    size_t progress_counter = 0;
+    auto test_paths = get_test_paths();
+    for (auto& path : test_paths) {
+        ++progress_counter;
+        print_file_result(run_file_test(path));
+        if (m_print_progress)
+            warn("\033]9;{};{};\033\\", progress_counter, test_paths.size());
+    }
+
+    if (m_print_progress)
+        warn("\033]9;-1;\033\\");
+
+    print_test_results();
+}
+
+static Result<NonnullRefPtr<JS::Program>, ParserError> parse_file(const String& file_path)
+{
+    auto file = Core::File::construct(file_path);
+    auto result = file->open(Core::IODevice::ReadOnly);
+    if (!result) {
+        warnln("Failed to open the following file: \"{}\"", file_path);
+        cleanup_and_exit();
+    }
+
+    auto contents = file->read_all();
+    String test_file_string(reinterpret_cast<const char*>(contents.data()), contents.size());
+    file->close();
+
+    auto parser = JS::Parser(JS::Lexer(test_file_string));
+    auto program = parser.parse_program();
+
+    if (parser.has_errors()) {
+        auto error = parser.errors()[0];
+        return Result<NonnullRefPtr<JS::Program>, ParserError>(ParserError { error, error.source_location_hint(test_file_string) });
+    }
+
+    return Result<NonnullRefPtr<JS::Program>, ParserError>(program);
+}
+
+static Optional<JsonValue> get_test_results(JS::Interpreter& interpreter)
+{
+    auto result = vm->get_variable("__TestResults__", interpreter.global_object());
+    auto json_string = JS::JSONObject::stringify_impl(interpreter.global_object(), result, JS::js_undefined(), JS::js_undefined());
+
+    auto json = JsonValue::from_string(json_string);
+    if (!json.has_value())
+        return {};
+
+    return json.value();
+}
+
+JSFileResult TestRunner::run_file_test(const String& test_path)
+{
+    currently_running_test = test_path;
+
+    double start_time = get_time_in_ms();
+    auto interpreter = JS::Interpreter::create<TestRunnerGlobalObject>(*vm);
+
+    // FIXME: This is a hack while we're refactoring Interpreter/VM stuff.
+    JS::VM::InterpreterExecutionScope scope(*interpreter);
+
+    interpreter->heap().set_should_collect_on_every_allocation(collect_on_every_allocation);
+
+    if (!m_test_program) {
+        auto result = parse_file(String::formatted("{}/test-common.js", m_test_root));
+        if (result.is_error()) {
+            warnln("Unable to parse test-common.js");
+            warnln("{}", result.error().error.to_string());
+            warnln("{}", result.error().hint);
+            cleanup_and_exit();
+        }
+        m_test_program = result.value();
+    }
+
+    interpreter->run(interpreter->global_object(), *m_test_program);
+
+    auto file_program = parse_file(test_path);
+    if (file_program.is_error())
+        return { test_path, file_program.error() };
+    interpreter->run(interpreter->global_object(), *file_program.value());
+
+    auto test_json = get_test_results(*interpreter);
+    if (!test_json.has_value()) {
+        warnln("Received malformed JSON from test \"{}\"", test_path);
+        cleanup_and_exit();
+    }
+
+    JSFileResult file_result { test_path.substring(m_test_root.length() + 1, test_path.length() - m_test_root.length() - 1) };
+
+    // Collect logged messages
+    auto& arr = interpreter->vm().get_variable("__UserOutput__", interpreter->global_object()).as_array();
+    for (auto& entry : arr.indexed_properties()) {
+        auto message = entry.value_and_attributes(&interpreter->global_object()).value;
+        file_result.logged_messages.append(message.to_string_without_side_effects());
+    }
+
+    test_json.value().as_object().for_each_member([&](const String& suite_name, const JsonValue& suite_value) {
+        Test::Suite suite { suite_name };
+
+        VERIFY(suite_value.is_object());
+
+        suite_value.as_object().for_each_member([&](const String& test_name, const JsonValue& test_value) {
+            Test::Case test { test_name, Test::Result::Fail, "" };
+
+            VERIFY(test_value.is_object());
+            VERIFY(test_value.as_object().has("result"));
+
+            auto result = test_value.as_object().get("result");
+            VERIFY(result.is_string());
+            auto result_string = result.as_string();
+            if (result_string == "pass") {
+                test.result = Test::Result::Pass;
+                m_counts.tests_passed++;
+            } else if (result_string == "fail") {
+                test.result = Test::Result::Fail;
+                m_counts.tests_failed++;
+                suite.most_severe_test_result = Test::Result::Fail;
+                VERIFY(test_value.as_object().has("details"));
+                auto details = test_value.as_object().get("details");
+                VERIFY(result.is_string());
+                test.details = details.as_string();
+            } else {
+                test.result = Test::Result::Skip;
+                if (suite.most_severe_test_result == Test::Result::Pass)
+                    suite.most_severe_test_result = Test::Result::Skip;
+                m_counts.tests_skipped++;
+            }
+
+            suite.tests.append(test);
+        });
+
+        if (suite.most_severe_test_result == Test::Result::Fail) {
+            m_counts.suites_failed++;
+            file_result.most_severe_test_result = Test::Result::Fail;
+        } else {
+            if (suite.most_severe_test_result == Test::Result::Skip && file_result.most_severe_test_result == Test::Result::Pass)
+                file_result.most_severe_test_result = Test::Result::Skip;
+            m_counts.suites_passed++;
+        }
+
+        file_result.suites.append(suite);
+    });
+
+    m_counts.files_total++;
+
+    file_result.time_taken = get_time_in_ms() - start_time;
+    m_total_elapsed_time_in_ms += file_result.time_taken;
+
+    return file_result;
+}
+
+enum Modifier {
+    BG_RED,
+    BG_GREEN,
+    FG_RED,
+    FG_GREEN,
+    FG_ORANGE,
+    FG_GRAY,
+    FG_BLACK,
+    FG_BOLD,
+    ITALIC,
+    CLEAR,
+};
+
+static void print_modifiers(Vector<Modifier> modifiers)
+{
+    for (auto& modifier : modifiers) {
+        auto code = [&] {
+            switch (modifier) {
+            case BG_RED:
+                return "\033[48;2;255;0;102m";
+            case BG_GREEN:
+                return "\033[48;2;102;255;0m";
+            case FG_RED:
+                return "\033[38;2;255;0;102m";
+            case FG_GREEN:
+                return "\033[38;2;102;255;0m";
+            case FG_ORANGE:
+                return "\033[38;2;255;102;0m";
+            case FG_GRAY:
+                return "\033[38;2;135;139;148m";
+            case FG_BLACK:
+                return "\033[30m";
+            case FG_BOLD:
+                return "\033[1m";
+            case ITALIC:
+                return "\033[3m";
+            case CLEAR:
+                return "\033[0m";
+            }
+            VERIFY_NOT_REACHED();
+        }();
+        out("{}", code);
+    }
+}
+
+void TestRunner::print_file_result(const JSFileResult& file_result) const
+{
+    if (file_result.most_severe_test_result == Test::Result::Fail || file_result.error.has_value()) {
+        print_modifiers({ BG_RED, FG_BLACK, FG_BOLD });
+        out(" FAIL ");
+        print_modifiers({ CLEAR });
+    } else {
+        if (m_print_times || file_result.most_severe_test_result != Test::Result::Pass) {
+            print_modifiers({ BG_GREEN, FG_BLACK, FG_BOLD });
+            out(" PASS ");
+            print_modifiers({ CLEAR });
+        } else {
+            return;
+        }
+    }
+
+    out(" {}", file_result.name);
+
+    if (m_print_times) {
+        print_modifiers({ CLEAR, ITALIC, FG_GRAY });
+        if (file_result.time_taken < 1000) {
+            outln(" ({}ms)", static_cast<int>(file_result.time_taken));
+        } else {
+            outln(" ({:3}s)", file_result.time_taken / 1000.0);
+        }
+        print_modifiers({ CLEAR });
+    } else {
+        outln();
+    }
+
+    if (!file_result.logged_messages.is_empty()) {
+        print_modifiers({ FG_GRAY, FG_BOLD });
+#ifdef __serenity__
+        outln("     ℹ Console output:");
+#else
+        // This emoji has a second invisible byte after it. The one above does not
+        outln("    ℹ️  Console output:");
+#endif
+        print_modifiers({ CLEAR, FG_GRAY });
+        for (auto& message : file_result.logged_messages)
+            outln("         {}", message);
+    }
+
+    if (file_result.error.has_value()) {
+        auto test_error = file_result.error.value();
+
+        print_modifiers({ FG_RED });
+#ifdef __serenity__
+        outln("     ❌ The file failed to parse");
+#else
+        // No invisible byte here, but the spacing still needs to be altered on the host
+        outln("    ❌ The file failed to parse");
+#endif
+        outln();
+        print_modifiers({ FG_GRAY });
+        for (auto& message : test_error.hint.split('\n', true)) {
+            outln("         {}", message);
+        }
+        print_modifiers({ FG_RED });
+        outln("         {}", test_error.error.to_string());
+        outln();
+        return;
+    }
+
+    if (file_result.most_severe_test_result != Test::Result::Pass) {
+        for (auto& suite : file_result.suites) {
+            if (suite.most_severe_test_result == Test::Result::Pass)
+                continue;
+
+            bool failed = suite.most_severe_test_result == Test::Result::Fail;
+
+            print_modifiers({ FG_GRAY, FG_BOLD });
+
+            if (failed) {
+#ifdef __serenity__
+                out("     ❌ Suite:  ");
+#else
+                // No invisible byte here, but the spacing still needs to be altered on the host
+                out("    ❌ Suite:  ");
+#endif
+            } else {
+#ifdef __serenity__
+                out("     ⚠ Suite:  ");
+#else
+                // This emoji has a second invisible byte after it. The one above does not
+                out("    ⚠️  Suite:  ");
+#endif
+            }
+
+            print_modifiers({ CLEAR, FG_GRAY });
+
+            if (suite.name == TOP_LEVEL_TEST_NAME) {
+                outln("<top-level>");
+            } else {
+                outln("{}", suite.name);
+            }
+            print_modifiers({ CLEAR });
+
+            for (auto& test : suite.tests) {
+                if (test.result == Test::Result::Pass)
+                    continue;
+
+                print_modifiers({ FG_GRAY, FG_BOLD });
+                out("         Test:   ");
+                if (test.result == Test::Result::Fail) {
+                    print_modifiers({ CLEAR, FG_RED });
+                    outln("{} (failed):", test.name);
+                    outln("                 {}", test.details);
+                } else {
+                    print_modifiers({ CLEAR, FG_ORANGE });
+                    outln("{} (skipped)", test.name);
+                }
+                print_modifiers({ CLEAR });
+            }
+        }
+    }
+}
+
+void TestRunner::print_test_results() const
+{
+    out("\nTest Suites: ");
+    if (m_counts.suites_failed) {
+        print_modifiers({ FG_RED });
+        out("{} failed, ", m_counts.suites_failed);
+        print_modifiers({ CLEAR });
+    }
+    if (m_counts.suites_passed) {
+        print_modifiers({ FG_GREEN });
+        out("{} passed, ", m_counts.suites_passed);
+        print_modifiers({ CLEAR });
+    }
+    outln("{} total", m_counts.suites_failed + m_counts.suites_passed);
+
+    out("Tests:       ");
+    if (m_counts.tests_failed) {
+        print_modifiers({ FG_RED });
+        out("{} failed, ", m_counts.tests_failed);
+        print_modifiers({ CLEAR });
+    }
+    if (m_counts.tests_skipped) {
+        print_modifiers({ FG_ORANGE });
+        out("{} skipped, ", m_counts.tests_skipped);
+        print_modifiers({ CLEAR });
+    }
+    if (m_counts.tests_passed) {
+        print_modifiers({ FG_GREEN });
+        out("{} passed, ", m_counts.tests_passed);
+        print_modifiers({ CLEAR });
+    }
+    outln("{} total", m_counts.tests_failed + m_counts.tests_skipped + m_counts.tests_passed);
+
+    outln("Files:       {} total", m_counts.files_total);
+
+    out("Time:        ");
+    if (m_total_elapsed_time_in_ms < 1000.0) {
+        outln("{}ms", static_cast<int>(m_total_elapsed_time_in_ms));
+    } else {
+        outln("{:>.3}s", m_total_elapsed_time_in_ms / 1000.0);
+    }
+    outln();
+}
+
+class Test262ParserTestRunner final : public TestRunner {
+public:
+    using TestRunner::TestRunner;
+
+private:
+    virtual Vector<String> get_test_paths() const override;
+    virtual JSFileResult run_file_test(const String& test_path) override;
+};
+
+Vector<String> Test262ParserTestRunner::get_test_paths() const
+{
+    Vector<String> paths;
+    iterate_directory_recursively(m_test_root, [&](const String& file_path) {
+        auto dirname = LexicalPath(file_path).dirname();
+        if (dirname.ends_with("early") || dirname.ends_with("fail") || dirname.ends_with("pass") || dirname.ends_with("pass-explicit"))
+            paths.append(file_path);
+    });
+    quick_sort(paths);
+    return paths;
+}
+
+JSFileResult Test262ParserTestRunner::run_file_test(const String& test_path)
+{
+    currently_running_test = test_path;
+
+    auto dirname = LexicalPath(test_path).dirname();
+    bool expecting_file_to_parse;
+    if (dirname.ends_with("early") || dirname.ends_with("fail")) {
+        expecting_file_to_parse = false;
+    } else if (dirname.ends_with("pass") || dirname.ends_with("pass-explicit")) {
+        expecting_file_to_parse = true;
+    } else {
+        VERIFY_NOT_REACHED();
+    }
+
+    auto start_time = get_time_in_ms();
+    String details = "";
+    Test::Result test_result;
+    if (test_path.ends_with(".module.js")) {
+        test_result = Test::Result::Skip;
+        m_counts.tests_skipped++;
+        m_counts.suites_passed++;
+    } else {
+        auto parse_result = parse_file(test_path);
+        if (expecting_file_to_parse) {
+            if (!parse_result.is_error()) {
+                test_result = Test::Result::Pass;
+            } else {
+                test_result = Test::Result::Fail;
+                details = parse_result.error().error.to_string();
+            }
+        } else {
+            if (parse_result.is_error()) {
+                test_result = Test::Result::Pass;
+            } else {
+                test_result = Test::Result::Fail;
+                details = "File was expected to produce a parser error but didn't";
+            }
+        }
+    }
+
+    // test262-parser-tests doesn't have "suites" and "tests" in the usual sense, it just has files
+    // and an expectation whether they should parse or not. We add one suite with one test nonetheless:
+    //
+    // - This makes interpreting skipped test easier as their file is shown as "PASS"
+    // - That way we can show additional information such as "file parsed but shouldn't have" or
+    //   parser errors for files that should parse respectively
+
+    Test::Case test { expecting_file_to_parse ? "file should parse" : "file should not parse", test_result, details };
+    Test::Suite suite { "Parse file", test_result, { test } };
+    JSFileResult file_result {
+        test_path.substring(m_test_root.length() + 1, test_path.length() - m_test_root.length() - 1),
+        {},
+        get_time_in_ms() - start_time,
+        test_result,
+        { suite }
+    };
+
+    if (test_result == Test::Result::Fail) {
+        m_counts.tests_failed++;
+        m_counts.suites_failed++;
+    } else {
+        m_counts.tests_passed++;
+        m_counts.suites_passed++;
+    }
+    m_counts.files_total++;
+    m_total_elapsed_time_in_ms += file_result.time_taken;
+
+    return file_result;
+}
+
+int main(int argc, char** argv)
+{
+    struct sigaction act;
+    memset(&act, 0, sizeof(act));
+    act.sa_flags = SA_NOCLDWAIT;
+    act.sa_handler = handle_sigabrt;
+    int rc = sigaction(SIGABRT, &act, nullptr);
+    if (rc < 0) {
+        perror("sigaction");
+        return 1;
+    }
+
+#ifdef SIGINFO
+    signal(SIGINFO, [](int) {
+        static char buffer[4096];
+        auto& counts = TestRunner::the()->counts();
+        int len = snprintf(buffer, sizeof(buffer), "Pass: %d, Fail: %d, Skip: %d\nCurrent test: %s\n", counts.tests_passed, counts.tests_failed, counts.tests_skipped, currently_running_test.characters());
+        write(STDOUT_FILENO, buffer, len);
+    });
+#endif
+
+    bool print_times = false;
+    bool print_progress =
+#ifdef __serenity__
+        true; // Use OSC 9 to print progress
+#else
+        false;
+#endif
+    bool test262_parser_tests = false;
+    const char* specified_test_root = nullptr;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(print_times, "Show duration of each test", "show-time", 't');
+    args_parser.add_option(Core::ArgsParser::Option {
+        .requires_argument = true,
+        .help_string = "Show progress with OSC 9 (true, false)",
+        .long_name = "show-progress",
+        .short_name = 'p',
+        .accept_value = [&](auto* str) {
+            if (StringView { "true" } == str)
+                print_progress = true;
+            else if (StringView { "false" } == str)
+                print_progress = false;
+            else
+                return false;
+            return true;
+        },
+    });
+    args_parser.add_option(collect_on_every_allocation, "Collect garbage after every allocation", "collect-often", 'g');
+    args_parser.add_option(test262_parser_tests, "Run test262 parser tests", "test262-parser-tests", 0);
+    args_parser.add_positional_argument(specified_test_root, "Tests root directory", "path", Core::ArgsParser::Required::No);
+    args_parser.parse(argc, argv);
+
+    if (test262_parser_tests) {
+        if (collect_on_every_allocation) {
+            warnln("--collect-often and --test262-parser-tests options must not be used together");
+            return 1;
+        }
+        if (!specified_test_root) {
+            warnln("Test root is required with --test262-parser-tests");
+            return 1;
+        }
+    }
+
+    if (getenv("DISABLE_DBG_OUTPUT")) {
+        AK::set_debug_enabled(false);
+    }
+
+    String test_root;
+
+    if (specified_test_root) {
+        test_root = String { specified_test_root };
+    } else {
+#ifdef __serenity__
+        test_root = "/home/anon/js-tests";
+#else
+        char* serenity_source_dir = getenv("SERENITY_SOURCE_DIR");
+        if (!serenity_source_dir) {
+            warnln("No test root given, test-js requires the SERENITY_SOURCE_DIR environment variable to be set");
+            return 1;
+        }
+        test_root = String::formatted("{}/Userland/Libraries/LibJS/Tests", serenity_source_dir);
+#endif
+    }
+    if (!Core::File::is_directory(test_root)) {
+        warnln("Test root is not a directory: {}", test_root);
+        return 1;
+    }
+
+    vm = JS::VM::create();
+
+    if (test262_parser_tests)
+        Test262ParserTestRunner(test_root, print_times, print_progress).run();
+    else
+        TestRunner(test_root, print_times, print_progress).run();
+
+    vm = nullptr;
+
+    return TestRunner::the()->counts().tests_failed > 0 ? 1 : 0;
+}