diff --git a/src/TestHTTPServer.zig b/src/TestHTTPServer.zig
new file mode 100644
index 00000000..11f44ee0
--- /dev/null
+++ b/src/TestHTTPServer.zig
@@ -0,0 +1,117 @@
+const std = @import("std");
+
+const TestHTTPServer = @This();
+
+shutdown: bool,
+listener: ?std.net.Server,
+handler: Handler,
+
+const Handler = *const fn (req: *std.http.Server.Request) anyerror!void;
+
+pub fn init(handler: Handler) TestHTTPServer {
+    return .{
+        .shutdown = true,
+        .listener = null,
+        .handler = handler,
+    };
+}
+
+pub fn deinit(self: *TestHTTPServer) void {
+    self.shutdown = true;
+    if (self.listener) |*listener| {
+        listener.deinit();
+    }
+}
+
+pub fn run(self: *TestHTTPServer, wg: *std.Thread.WaitGroup) !void {
+    const address = try std.net.Address.parseIp("127.0.0.1", 9582);
+
+    self.listener = try address.listen(.{ .reuse_address = true });
+    var listener = &self.listener.?;
+
+    wg.finish();
+
+    while (true) {
+        const conn = listener.accept() catch |err| {
+            if (self.shutdown) {
+                return;
+            }
+            return err;
+        };
+        const thrd = try std.Thread.spawn(.{}, handleConnection, .{ self, conn });
+        thrd.detach();
+    }
+}
+
+fn handleConnection(self: *TestHTTPServer, conn: std.net.Server.Connection) !void {
+    defer conn.stream.close();
+
+    var req_buf: [2048]u8 = undefined;
+    var conn_reader = conn.stream.reader(&req_buf);
+    var conn_writer = conn.stream.writer(&req_buf);
+
+    var http_server = std.http.Server.init(conn_reader.interface(), &conn_writer.interface);
+
+    while (true) {
+        var req = http_server.receiveHead() catch |err| switch (err) {
+            error.ReadFailed => continue,
+            error.HttpConnectionClosing => continue,
+            else => {
+                std.debug.print("Test HTTP Server error: {}\n", .{err});
+                return err;
+            },
+        };
+        self.handler(&req) catch |err| {
+            std.debug.print("test http error '{s}': {}\n", .{ req.head.target, err });
+            try req.respond("server error", .{ .status = .internal_server_error });
+            return;
+        };
+    }
+}
+
+pub fn sendFile(req: *std.http.Server.Request, file_path: []const u8) !void {
+    var file = std.fs.cwd().openFile(file_path, .{}) catch |err| switch (err) {
+        error.FileNotFound => return req.respond("server error", .{ .status = .not_found }),
+        else => return err,
+    };
+
+    const stat = try file.stat();
+    var send_buffer: [4096]u8 = undefined;
+
+    var res = try req.respondStreaming(&send_buffer, .{
+        .content_length = stat.size,
+        .respond_options = .{
+            .extra_headers = &.{
+                .{ .name = "content-type", .value = getContentType(file_path) },
+            },
+        },
+    });
+
+    var read_buffer: [4096]u8 = undefined;
+    var reader = file.reader(&read_buffer);
+    _ = try res.writer.sendFileAll(&reader, .unlimited);
+    try res.writer.flush();
+    try res.end();
+}
+
+fn getContentType(file_path: []const u8) []const u8 {
+    if (std.mem.endsWith(u8, file_path, ".js")) {
+        return "application/json";
+    }
+
+    if (std.mem.endsWith(u8, file_path, ".html")) {
+        return "text/html";
+    }
+
+    if (std.mem.endsWith(u8, file_path, ".htm")) {
+        return "text/html";
+    }
+
+    if (std.mem.endsWith(u8, file_path, ".xml")) {
+        // some wpt tests do this
+        return "text/xml";
+    }
+
+    std.debug.print("TestHTTPServer asked to serve an unknown file type: {s}\n", .{file_path});
+    return "text/html";
+}
diff --git a/src/browser/ScriptManager.zig b/src/browser/ScriptManager.zig
index 269d1de7..ca6626f4 100644
--- a/src/browser/ScriptManager.zig
+++ b/src/browser/ScriptManager.zig
@@ -403,14 +403,7 @@ fn startCallback(transfer: *Http.Transfer) !void {
 
 fn headerCallback(transfer: *Http.Transfer) !void {
     const script: *PendingScript = @ptrCast(@alignCast(transfer.ctx));
-    script.headerCallback(transfer) catch |err| {
-        log.err(.http, "SM.headerCallback", .{
-            .err = err,
-            .transfer = transfer,
-            .status = transfer.response_header.?.status,
-        });
-        return err;
-    };
+    script.headerCallback(transfer);
 }
 
 fn dataCallback(transfer: *Http.Transfer, data: []const u8) !void {
@@ -463,18 +456,23 @@ const PendingScript = struct {
         log.debug(.http, "script fetch start", .{ .req = transfer });
     }
 
-    fn headerCallback(self: *PendingScript, transfer: *Http.Transfer) !void {
+    fn headerCallback(self: *PendingScript, transfer: *Http.Transfer) void {
         const header = &transfer.response_header.?;
+        if (header.status != 200) {
+            log.info(.http, "script header", .{
+                .req = transfer,
+                .status = header.status,
+                .content_type = header.contentType(),
+            });
+            return;
+        }
+
         log.debug(.http, "script header", .{
             .req = transfer,
             .status = header.status,
             .content_type = header.contentType(),
         });
 
-        if (header.status != 200) {
-            return error.InvalidStatusCode;
-        }
-
         // If this isn't true, then we'll likely leak memory. If you don't
         // set `CURLOPT_SUPPRESS_CONNECT_HEADERS` and CONNECT to a proxy, this
         // will fail. This assertion exists to catch incorrect assumptions about
diff --git a/src/browser/xhr/xhr.zig b/src/browser/xhr/xhr.zig
index 09891c20..afdaedee 100644
--- a/src/browser/xhr/xhr.zig
+++ b/src/browser/xhr/xhr.zig
@@ -789,8 +789,7 @@ test "Browser.XHR.XMLHttpRequest" {
         .{ "req.statusText", "OK" },
         .{ "req.getResponseHeader('Content-Type')", "text/html; charset=utf-8" },
         .{ "req.getAllResponseHeaders()", "content-length: 100\r\n" ++
-            "Content-Type: text/html; charset=utf-8\r\n" ++
-            "Connection: Close\r\n" },
+            "Content-Type: text/html; charset=utf-8\r\n" },
         .{ "req.responseText.length", "100" },
         .{ "req.response.length == req.responseText.length", "true" },
         .{ "req.responseXML instanceof Document", "true" },
diff --git a/src/main.zig b/src/main.zig
index fb02932f..35bcf7df 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -719,23 +719,26 @@ test {
     std.testing.refAllDecls(@This());
 }
 
+const TestHTTPServer = @import("TestHTTPServer.zig");
+
 var test_cdp_server: ?Server = null;
+var test_http_server: ?TestHTTPServer = null;
+
 test "tests:beforeAll" {
     log.opts.level = .err;
     log.opts.format = .logfmt;
-
     try testing.setup();
-
     var wg: std.Thread.WaitGroup = .{};
     wg.startMany(2);
 
     {
-        const thread = try std.Thread.spawn(.{}, serveHTTP, .{&wg});
+        const thread = try std.Thread.spawn(.{}, serveCDP, .{&wg});
         thread.detach();
     }
 
+    test_http_server = TestHTTPServer.init(testHTTPHandler);
     {
-        const thread = try std.Thread.spawn(.{}, serveCDP, .{&wg});
+        const thread = try std.Thread.spawn(.{}, TestHTTPServer.run, .{ &test_http_server.?, &wg });
         thread.detach();
     }
 
@@ -748,59 +751,10 @@ test "tests:afterAll" {
     if (test_cdp_server) |*server| {
         server.deinit();
     }
-    testing.shutdown();
-}
-
-fn serveHTTP(wg: *std.Thread.WaitGroup) !void {
-    const address = try std.net.Address.parseIp("127.0.0.1", 9582);
-
-    var listener = try address.listen(.{ .reuse_address = true });
-    defer listener.deinit();
-
-    wg.finish();
-
-    var buf: [1024]u8 = undefined;
-    while (true) {
-        var conn = try listener.accept();
-        defer conn.stream.close();
-        var conn_reader = conn.stream.reader(&buf);
-        var conn_writer = conn.stream.writer(&buf);
-
-        var http_server = std.http.Server.init(conn_reader.interface(), &conn_writer.interface);
-
-        var request = http_server.receiveHead() catch |err| switch (err) {
-            error.HttpConnectionClosing => continue,
-            else => {
-                std.debug.print("Test HTTP Server error: {}\n", .{err});
-                return err;
-            },
-        };
-
-        const path = request.head.target;
-
-        if (std.mem.eql(u8, path, "/loader")) {
-            try request.respond("Hello!", .{
-                .extra_headers = &.{.{ .name = "Connection", .value = "close" }},
-            });
-        } else if (std.mem.eql(u8, path, "/xhr")) {
-            try request.respond("1234567890" ** 10, .{
-                .extra_headers = &.{
-                    .{ .name = "Content-Type", .value = "text/html; charset=utf-8" },
-                    .{ .name = "Connection", .value = "Close" },
-                },
-            });
-        } else if (std.mem.eql(u8, path, "/xhr/json")) {
-            try request.respond("{\"over\":\"9000!!!\"}", .{
-                .extra_headers = &.{
-                    .{ .name = "Content-Type", .value = "application/json" },
-                    .{ .name = "Connection", .value = "Close" },
-                },
-            });
-        } else {
-            // should not have an unknown path
-            unreachable;
-        }
+    if (test_http_server) |*server| {
+        server.deinit();
     }
+    testing.shutdown();
 }
 
 fn serveCDP(wg: *std.Thread.WaitGroup) !void {
@@ -816,3 +770,31 @@ fn serveCDP(wg: *std.Thread.WaitGroup) !void {
         return err;
     };
 }
+
+fn testHTTPHandler(req: *std.http.Server.Request) !void {
+    const path = req.head.target;
+
+    if (std.mem.eql(u8, path, "/loader")) {
+        return req.respond("Hello!", .{
+            .extra_headers = &.{.{ .name = "Connection", .value = "close" }},
+        });
+    }
+
+    if (std.mem.eql(u8, path, "/xhr")) {
+        return req.respond("1234567890" ** 10, .{
+            .extra_headers = &.{
+                .{ .name = "Content-Type", .value = "text/html; charset=utf-8" },
+            },
+        });
+    }
+
+    if (std.mem.eql(u8, path, "/xhr/json")) {
+        return req.respond("{\"over\":\"9000!!!\"}", .{
+            .extra_headers = &.{
+                .{ .name = "Content-Type", .value = "application/json" },
+            },
+        });
+    }
+
+    unreachable;
+}
diff --git a/src/main_wpt.zig b/src/main_wpt.zig
index f70aaed3..7a4f9d8e 100644
--- a/src/main_wpt.zig
+++ b/src/main_wpt.zig
@@ -22,24 +22,34 @@ const log = @import("log.zig");
 const Allocator = std.mem.Allocator;
 const ArenaAllocator = std.heap.ArenaAllocator;
 
+const App = @import("app.zig").App;
 const Env = @import("browser/env.zig").Env;
-const Platform = @import("runtime/js.zig").Platform;
+const Browser = @import("browser/browser.zig").Browser;
+const Session = @import("browser/session.zig").Session;
+const TestHTTPServer = @import("TestHTTPServer.zig");
 
 const parser = @import("browser/netsurf.zig");
 const polyfill = @import("browser/polyfill/polyfill.zig");
 
 const WPT_DIR = "tests/wpt";
 
-// TODO For now the WPT tests run is specific to WPT.
-// It manually load js framwork libs, and run the first script w/ js content in
-// the HTML page.
-// Once lightpanda will have the html loader, it would be useful to refactor
-// this test to use it.
 pub fn main() !void {
     var gpa: std.heap.DebugAllocator(.{}) = .init;
     defer _ = gpa.deinit();
+
     const allocator = gpa.allocator();
-    log.opts.level = .warn;
+    log.opts.level = .err;
+
+    var http_server = TestHTTPServer.init(httpHandler);
+    defer http_server.deinit();
+
+    {
+        var wg: std.Thread.WaitGroup = .{};
+        wg.startMany(1);
+        var thrd = try std.Thread.spawn(.{}, TestHTTPServer.run, .{ &http_server, &wg });
+        thrd.detach();
+        wg.wait();
+    }
 
     // An arena for the runner itself, lives for the duration of the the process
     var ra = ArenaAllocator.init(allocator);
@@ -48,29 +58,33 @@ pub fn main() !void {
 
     const cmd = try parseArgs(runner_arena);
 
-    try @import("testing.zig").setup();
-    defer @import("testing.zig").shutdown();
-
-    // prepare libraries to load on each test case.
-    var loader = FileLoader.init(runner_arena, WPT_DIR);
-
-    var it = try TestIterator.init(runner_arena, WPT_DIR, cmd.filters);
+    var it = try TestIterator.init(allocator, WPT_DIR, cmd.filters);
     defer it.deinit();
 
-    var writer = try Writer.init(runner_arena, cmd.format);
+    var writer = try Writer.init(allocator, cmd.format);
+    defer writer.deinit();
 
     // An arena for running each tests. Is reset after every test.
     var test_arena = ArenaAllocator.init(allocator);
     defer test_arena.deinit();
 
+    var app = try App.init(allocator, .{
+        .run_mode = .fetch,
+    });
+    defer app.deinit();
+
+    var browser = try Browser.init(app);
+    defer browser.deinit();
+    const session = try browser.newSession();
+
     while (try it.next()) |test_file| {
-        defer _ = test_arena.reset(.{ .retain_capacity = {} });
+        defer _ = test_arena.reset(.retain_capacity);
 
         var err_out: ?[]const u8 = null;
         const result = run(
             test_arena.allocator(),
+            session,
             test_file,
-            &loader,
             &err_out,
         ) catch |err| blk: {
             if (err_out == null) {
@@ -78,13 +92,6 @@ pub fn main() !void {
             }
             break :blk null;
         };
-
-        if (result == null and err_out == null) {
-            // We sometimes pass a non-test to `run` (we don't know it's a non
-            // test, we need to open the contents of the test file to find out
-            // and that's in run).
-            continue;
-        }
         try writer.process(test_file, result, err_out);
     }
     try writer.finalize();
@@ -92,102 +99,41 @@ pub fn main() !void {
 
 fn run(
     arena: Allocator,
+    session: *Session,
     test_file: []const u8,
-    loader: *FileLoader,
     err_out: *?[]const u8,
-) !?[]const u8 {
-    // document
-    const html = blk: {
-        const full_path = try std.fs.path.join(arena, &.{ WPT_DIR, test_file });
-        const file = try std.fs.cwd().openFile(full_path, .{});
-        defer file.close();
-        break :blk try file.readToEndAlloc(arena, 128 * 1024);
-    };
+) ![]const u8 {
+    const page = try session.createPage();
+    defer session.removePage();
 
-    if (std.mem.indexOf(u8, html, "testharness.js") == null) {
-        // This isn't a test. A lot of files are helpers/content for tests to
-        // make use of.
-        return null;
-    }
+    const url = try std.fmt.allocPrint(arena, "http://localhost:9582/{s}", .{test_file});
+    try page.navigate(url, .{});
 
-    // this returns null for the success.html test in the root of tests/wpt
-    const dirname = std.fs.path.dirname(test_file) orelse "";
+    page.wait(2);
 
-    var runner = try @import("testing.zig").jsRunner(arena, .{
-        .url = "http://127.0.0.1",
-        .html = html,
-    });
-    defer runner.deinit();
-
-    defer if (err_out.*) |eo| {
-        // the error might be owned by the runner, we'll dupe it with our
-        // own arena so that it can be returned out of this function.
-        err_out.* = arena.dupe(u8, eo) catch "failed to dupe error";
-    };
-
-    try polyfill.preload(arena, runner.page.main_context);
-
-    // loop over the scripts.
-    const doc = parser.documentHTMLToDocument(runner.page.window.document);
-    const scripts = try parser.documentGetElementsByTagName(doc, "script");
-    const script_count = try parser.nodeListLength(scripts);
-    for (0..script_count) |i| {
-        const s = (try parser.nodeListItem(scripts, @intCast(i))).?;
-
-        // If the script contains an src attribute, load it.
-        if (try parser.elementGetAttribute(@as(*parser.Element, @ptrCast(s)), "src")) |src| {
-            var path = src;
-            if (!std.mem.startsWith(u8, src, "/")) {
-                path = try std.fs.path.join(arena, &.{ "/", dirname, path });
-            }
-            const script_source = loader.get(path) catch |err| {
-                err_out.* = std.fmt.allocPrint(arena, "{s} - {s}", .{ @errorName(err), path }) catch null;
-                return err;
-            };
-            try runner.exec(script_source, src, err_out);
-        }
-
-        // If the script as a source text, execute it.
-        const src = try parser.nodeTextContent(s) orelse continue;
-        try runner.exec(src, null, err_out);
-    }
-
-    {
-        // Mark tests as ready to run.
-        const loadevt = try parser.eventCreate();
-        defer parser.eventDestroy(loadevt);
-
-        try parser.eventInit(loadevt, "load", .{});
-        _ = try parser.eventTargetDispatchEvent(
-            parser.toEventTarget(@TypeOf(runner.page.window), &runner.page.window),
-            loadevt,
-        );
-    }
-
-    {
-        // wait for all async executions
-        var try_catch: Env.TryCatch = undefined;
-        try_catch.init(runner.page.main_context);
-        defer try_catch.deinit();
-        runner.page.wait(2);
-
-        if (try_catch.hasCaught()) {
-            err_out.* = (try try_catch.err(arena)) orelse "unknwon error";
-        }
-    }
+    const js_context = page.main_context;
+    var try_catch: Env.TryCatch = undefined;
+    try_catch.init(js_context);
+    defer try_catch.deinit();
 
     // Check the final test status.
-    try runner.exec("report.status", "teststatus", err_out);
+    js_context.eval("report.status", "teststatus") catch |err| {
+        err_out.* = try_catch.err(arena) catch @errorName(err) orelse "unknown";
+        return err;
+    };
 
     // return the detailed result.
-    const res = try runner.eval("report.log", "report", err_out);
+    const value = js_context.exec("report.log", "report") catch |err| {
+        err_out.* = try_catch.err(arena) catch @errorName(err) orelse "unknown";
+        return err;
+    };
 
-    return try res.toString(arena);
+    return value.toString(arena);
 }
 
 const Writer = struct {
     format: Format,
-    arena: Allocator,
+    allocator: Allocator,
     pass_count: usize = 0,
     fail_count: usize = 0,
     case_pass_count: usize = 0,
@@ -201,7 +147,7 @@ const Writer = struct {
         summary,
     };
 
-    fn init(arena: Allocator, format: Format) !Writer {
+    fn init(allocator: Allocator, format: Format) !Writer {
         const out = std.fs.File.stdout();
         var writer = out.writer(&.{});
 
@@ -210,12 +156,16 @@ const Writer = struct {
         }
 
         return .{
-            .arena = arena,
             .format = format,
             .writer = writer,
+            .allocator = allocator,
         };
     }
 
+    fn deinit(self: *Writer) void {
+        self.cases.deinit(self.allocator);
+    }
+
     fn finalize(self: *Writer) !void {
         var writer = &self.writer.interface;
         if (self.format == .json) {
@@ -303,7 +253,7 @@ const Writer = struct {
                 case_fail_count += 1;
             }
 
-            try cases.append(self.arena, .{
+            try cases.append(self.allocator, .{
                 .name = case_name,
                 .pass = case_pass,
                 .message = case_message,
@@ -396,22 +346,26 @@ const TestIterator = struct {
     dir: Dir,
     walker: Dir.Walker,
     filters: [][]const u8,
+    read_arena: ArenaAllocator,
 
     const Dir = std.fs.Dir;
 
-    fn init(arena: Allocator, root: []const u8, filters: [][]const u8) !TestIterator {
+    fn init(allocator: Allocator, root: []const u8, filters: [][]const u8) !TestIterator {
         var dir = try std.fs.cwd().openDir(root, .{ .iterate = true, .no_follow = true });
         errdefer dir.close();
 
         return .{
             .dir = dir,
             .filters = filters,
-            .walker = try dir.walk(arena),
+            .walker = try dir.walk(allocator),
+            .read_arena = ArenaAllocator.init(allocator),
         };
     }
 
     fn deinit(self: *TestIterator) void {
+        self.walker.deinit();
         self.dir.close();
+        self.read_arena.deinit();
     }
 
     fn next(self: *TestIterator) !?[]const u8 {
@@ -436,6 +390,25 @@ const TestIterator = struct {
                 }
             }
 
+            {
+                defer _ = self.read_arena.reset(.retain_capacity);
+                // We need to read the file's content to see if there's a
+                // "testharness.js" in it. If there isn't, it isn't a test.
+                // Shame we have to do this.
+
+                const arena = self.read_arena.allocator();
+                const full_path = try std.fs.path.join(arena, &.{ WPT_DIR, path });
+                const file = try std.fs.cwd().openFile(full_path, .{});
+                defer file.close();
+                const html = try file.readToEndAlloc(arena, 128 * 1024);
+
+                if (std.mem.indexOf(u8, html, "testharness.js") == null) {
+                    // This isn't a test. A lot of files are helpers/content for tests to
+                    // make use of.
+                    continue :NEXT;
+                }
+            }
+
             return path;
         }
 
@@ -456,35 +429,16 @@ const Test = struct {
     cases: []Case,
 };
 
-pub const FileLoader = struct {
-    path: []const u8,
-    arena: Allocator,
-    files: std.StringHashMapUnmanaged([]const u8),
+fn httpHandler(req: *std.http.Server.Request) !void {
+    const path = req.head.target;
 
-    pub fn init(arena: Allocator, path: []const u8) FileLoader {
-        return .{
-            .path = path,
-            .files = .{},
-            .arena = arena,
-        };
-    }
-    pub fn get(self: *FileLoader, name: []const u8) ![]const u8 {
-        const gop = try self.files.getOrPut(self.arena, name);
-        if (gop.found_existing == false) {
-            gop.key_ptr.* = try self.arena.dupe(u8, name);
-            gop.value_ptr.* = self.load(name) catch |err| {
-                _ = self.files.remove(name);
-                return err;
-            };
-        }
-        return gop.value_ptr.*;
+    if (std.mem.eql(u8, path, "/")) {
+        // There's 1 test that does an XHR request to this, and it just seems
+        // to want a 200 success.
+        return req.respond("Hello!", .{});
     }
 
-    fn load(self: *FileLoader, name: []const u8) ![]const u8 {
-        const filename = try std.fs.path.join(self.arena, &.{ self.path, name });
-        var file = try std.fs.cwd().openFile(filename, .{});
-        defer file.close();
-
-        return file.readToEndAlloc(self.arena, 4 * 1024 * 1024);
-    }
-};
+    var buf: [1024]u8 = undefined;
+    const file_path = try std.fmt.bufPrint(&buf, WPT_DIR ++ "{s}", .{path});
+    return TestHTTPServer.sendFile(req, file_path);
+}
diff --git a/src/runtime/js.zig b/src/runtime/js.zig
index 134fa777..ca16305e 100644
--- a/src/runtime/js.zig
+++ b/src/runtime/js.zig
@@ -1516,12 +1516,12 @@ pub fn Env(comptime State: type, comptime WebApis: type) type {
                 }
 
                 const op = js_obj.getInternalField(0).castTo(v8.External).get();
-                const toa: *TaggedAnyOpaque = @ptrCast(@alignCast(op));
+                const tao: *TaggedAnyOpaque = @ptrCast(@alignCast(op));
                 const expected_type_index = @field(TYPE_LOOKUP, type_name);
 
-                var type_index = toa.index;
+                var type_index = tao.index;
                 if (type_index == expected_type_index) {
-                    return @ptrCast(@alignCast(toa.ptr));
+                    return @ptrCast(@alignCast(tao.ptr));
                 }
 
                 const meta_lookup = self.meta_lookup;
@@ -1533,7 +1533,7 @@ pub fn Env(comptime State: type, comptime WebApis: type) type {
                 // ...unless, the proto is behind a pointer, then total_offset will
                 // get reset to 0, and our base_ptr will move to the address
                 // referenced by the proto field.
-                var base_ptr: usize = @intFromPtr(toa.ptr);
+                var base_ptr: usize = @intFromPtr(tao.ptr);
 
                 // search through the prototype tree
                 while (true) {