diff --git a/Makefile b/Makefile
index 6dff85e5..4b824f11 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,8 @@
 
 ZIG := zig
 BC := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
+# option test filter make unittest F="server"
+F=
 
 # OS and ARCH
 kernel = $(shell uname -ms)
@@ -42,7 +44,7 @@ help:
 
 # $(ZIG) commands
 # ------------
-.PHONY: build build-dev run run-release shell test bench download-zig wpt
+.PHONY: build build-dev run run-release shell test bench download-zig wpt unittest
 
 zig_version = $(shell grep 'recommended_zig_version = "' "vendor/zig-js-runtime/build.zig" | cut -d'"' -f2)
 
@@ -91,6 +93,9 @@ test:
 	@$(ZIG) build test -Dengine=v8 || (printf "\e[33mTest ERROR\e[0m\n"; exit 1;)
 	@printf "\e[33mTest OK\e[0m\n"
 
+unittest:
+	@TEST_FILTER='${F}' $(ZIG) build unittest -freference-trace --summary all
+
 # Install and build required dependencies commands
 # ------------
 .PHONY: install-submodule
diff --git a/build.zig b/build.zig
index b937252a..44e99222 100644
--- a/build.zig
+++ b/build.zig
@@ -98,8 +98,8 @@ pub fn build(b: *std.Build) !void {
 
     // compile
     const tests = b.addTest(.{
-        .root_source_file = b.path("src/run_tests.zig"),
-        .test_runner = b.path("src/test_runner.zig"),
+        .root_source_file = b.path("src/main_tests.zig"),
+        .test_runner = b.path("src/main_tests.zig"),
         .target = target,
         .optimize = mode,
     });
@@ -119,6 +119,27 @@ pub fn build(b: *std.Build) !void {
     const test_step = b.step("test", "Run unit tests");
     test_step.dependOn(&run_tests.step);
 
+    // unittest
+    // ----
+
+    // compile
+    const unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/unit_tests.zig"),
+        .test_runner = b.path("src/unit_tests.zig"),
+        .target = target,
+        .optimize = mode,
+    });
+    try common(b, unit_tests, options);
+
+    const run_unit_tests = b.addRunArtifact(unit_tests);
+    if (b.args) |args| {
+        run_unit_tests.addArgs(args);
+    }
+
+    // step
+    const unit_test_step = b.step("unittest", "Run unit tests");
+    unit_test_step.dependOn(&run_unit_tests.step);
+
     // wpt
     // -----
 
diff --git a/src/browser/loader.zig b/src/browser/loader.zig
index 480ec4c1..6df6d9ad 100644
--- a/src/browser/loader.zig
+++ b/src/browser/loader.zig
@@ -79,13 +79,19 @@ pub const Loader = struct {
     }
 };
 
-test "basic url get" {
+test "loader: get" {
     const alloc = std.testing.allocator;
     var loader = Loader.init(alloc);
     defer loader.deinit();
 
-    var result = try loader.get(alloc, "https://en.wikipedia.org/wiki/Main_Page");
+    const uri = try std.Uri.parse("http://localhost:9582/loader");
+    var result = try loader.get(alloc, uri);
     defer result.deinit();
 
-    try std.testing.expect(result.req.response.status == std.http.Status.ok);
+    try std.testing.expectEqual(.ok, result.req.response.status);
+
+    var res: [128]u8 = undefined;
+    const size = try result.req.readAll(&res);
+    try std.testing.expectEqual(6, size);
+    try std.testing.expectEqualStrings("Hello!", res[0..6]);
 }
diff --git a/src/iterator/iterator.zig b/src/iterator/iterator.zig
index 803cd978..d582be11 100644
--- a/src/iterator/iterator.zig
+++ b/src/iterator/iterator.zig
@@ -15,19 +15,39 @@ pub const U32Iterator = struct {
         done: bool,
     };
 
-    pub fn _next(self: *U32Iterator) !Return {
+    pub fn _next(self: *U32Iterator) Return {
         const i = self.index;
         if (i >= self.length) {
-            return Return{
+            return .{
                 .value = 0,
                 .done = true,
             };
         }
 
-        self.index += 1;
-        return Return{
+        self.index = i + 1;
+        return .{
             .value = i,
             .done = false,
         };
     }
 };
+
+const testing = std.testing;
+test "U32Iterator" {
+    const Return = U32Iterator.Return;
+
+    {
+        var it = U32Iterator{ .length = 0 };
+        try testing.expectEqual(Return{ .value = 0, .done = true }, it._next());
+        try testing.expectEqual(Return{ .value = 0, .done = true }, it._next());
+    }
+
+    {
+        var it = U32Iterator{ .length = 3 };
+        try testing.expectEqual(Return{ .value = 0, .done = false }, it._next());
+        try testing.expectEqual(Return{ .value = 1, .done = false }, it._next());
+        try testing.expectEqual(Return{ .value = 2, .done = false }, it._next());
+        try testing.expectEqual(Return{ .value = 0, .done = true }, it._next());
+        try testing.expectEqual(Return{ .value = 0, .done = true }, it._next());
+    }
+}
diff --git a/src/run_tests.zig b/src/main_tests.zig
similarity index 97%
rename from src/run_tests.zig
rename to src/main_tests.zig
index 9c0c98b9..3544cc6a 100644
--- a/src/run_tests.zig
+++ b/src/main_tests.zig
@@ -223,8 +223,14 @@ pub fn main() !void {
             try parser.init();
             defer parser.deinit();
 
+            std.testing.allocator_instance = .{};
             try test_fn.func();
-            std.debug.print("{s}\tOK\n", .{test_fn.name});
+
+            if (std.testing.allocator_instance.deinit() == .leak) {
+                std.debug.print("======Memory Leak: {s}======\n", .{test_fn.name});
+            } else {
+                std.debug.print("{s}\tOK\n", .{test_fn.name});
+            }
         }
     }
 }
diff --git a/src/storage/storage.zig b/src/storage/storage.zig
index 205a3895..53b5e42b 100644
--- a/src/storage/storage.zig
+++ b/src/storage/storage.zig
@@ -149,20 +149,22 @@ pub const Bottle = struct {
     }
 
     pub fn _setItem(self: *Bottle, k: []const u8, v: []const u8) !void {
-        const old = self.map.get(k);
-        if (old != null and std.mem.eql(u8, v, old.?)) return;
-
-        // owns k and v by copying them.
-        const kk = try self.alloc.dupe(u8, k);
-        errdefer self.alloc.free(kk);
-        const vv = try self.alloc.dupe(u8, v);
-        errdefer self.alloc.free(vv);
-
-        self.map.put(self.alloc, kk, vv) catch |e| {
+        const gop = self.map.getOrPut(self.alloc, k) catch |e| {
             log.debug("set item: {any}", .{e});
             return DOMError.QuotaExceeded;
         };
 
+        if (gop.found_existing == false) {
+            gop.key_ptr.* = try self.alloc.dupe(u8, k);
+            gop.value_ptr.* = try self.alloc.dupe(u8, v);
+            return;
+        }
+
+        if (std.mem.eql(u8, v, gop.value_ptr.*) == false) {
+            self.alloc.free(gop.value_ptr.*);
+            gop.value_ptr.* = try self.alloc.dupe(u8, v);
+        }
+
         // > Broadcast this with key, oldValue, and value.
         // https://html.spec.whatwg.org/multipage/webstorage.html#the-storageevent-interface
         //
@@ -175,8 +177,10 @@ pub const Bottle = struct {
     }
 
     pub fn _removeItem(self: *Bottle, k: []const u8) !void {
-        const old = self.map.fetchRemove(k);
-        if (old == null) return;
+        if (self.map.fetchRemove(k)) |kv| {
+            self.alloc.free(kv.key);
+            self.alloc.free(kv.value);
+        }
 
         // > Broadcast this with key, oldValue, and null.
         // https://html.spec.whatwg.org/multipage/webstorage.html#the-storageevent-interface
@@ -235,14 +239,17 @@ test "storage bottle" {
     var bottle = Bottle.init(std.testing.allocator);
     defer bottle.deinit();
 
-    try std.testing.expect(0 == bottle.get_length());
-    try std.testing.expect(null == bottle._getItem("foo"));
+    try std.testing.expectEqual(0, bottle.get_length());
+    try std.testing.expectEqual(null, bottle._getItem("foo"));
 
     try bottle._setItem("foo", "bar");
-    try std.testing.expect(std.mem.eql(u8, "bar", bottle._getItem("foo").?));
+    try std.testing.expectEqualStrings("bar", bottle._getItem("foo").?);
+
+    try bottle._setItem("foo", "other");
+    try std.testing.expectEqualStrings("other", bottle._getItem("foo").?);
 
     try bottle._removeItem("foo");
 
-    try std.testing.expect(0 == bottle.get_length());
-    try std.testing.expect(null == bottle._getItem("foo"));
+    try std.testing.expectEqual(0, bottle.get_length());
+    try std.testing.expectEqual(null, bottle._getItem("foo"));
 }
diff --git a/src/test_runner.zig b/src/test_runner.zig
deleted file mode 100644
index 8358b66c..00000000
--- a/src/test_runner.zig
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
-//
-// Francis Bouvier <francis@lightpanda.io>
-// Pierre Tachoire <pierre@lightpanda.io>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as
-// published by the Free Software Foundation, either version 3 of the
-// License, or (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-const std = @import("std");
-
-const tests = @import("run_tests.zig");
-
-pub const Types = tests.Types;
-pub const UserContext = tests.UserContext;
-pub const IO = tests.IO;
-
-pub fn main() !void {
-    try tests.main();
-}
diff --git a/src/unit_tests.zig b/src/unit_tests.zig
new file mode 100644
index 00000000..2ab87f9a
--- /dev/null
+++ b/src/unit_tests.zig
@@ -0,0 +1,347 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const builtin = @import("builtin");
+
+const Allocator = std.mem.Allocator;
+
+pub const std_options = std.Options{
+    .http_disable_tls = true,
+};
+
+const BORDER = "=" ** 80;
+
+// use in custom panic handler
+var current_test: ?[]const u8 = null;
+
+pub fn main() !void {
+    var mem: [8192]u8 = undefined;
+    var fba = std.heap.FixedBufferAllocator.init(&mem);
+
+    const allocator = fba.allocator();
+
+    const env = Env.init(allocator);
+    defer env.deinit(allocator);
+
+    var slowest = SlowTracker.init(allocator, 5);
+    defer slowest.deinit();
+
+    var pass: usize = 0;
+    var fail: usize = 0;
+    var skip: usize = 0;
+    var leak: usize = 0;
+
+    const address = try std.net.Address.parseIp("127.0.0.1", 9582);
+    var listener = try address.listen(.{ .reuse_address = true });
+    defer listener.deinit();
+    const http_thread = try std.Thread.spawn(.{}, serverHTTP, .{&listener});
+    defer http_thread.join();
+
+    const printer = Printer.init();
+    printer.fmt("\r\x1b[0K", .{}); // beginning of line and clear to end of line
+
+    for (builtin.test_functions) |t| {
+        if (std.mem.eql(u8, t.name, "unit_tests.test_0")) {
+            // don't display anything for this test
+            try t.func();
+            continue;
+        }
+
+        var status = Status.pass;
+        slowest.startTiming();
+
+        const is_unnamed_test = isUnnamed(t);
+        if (env.filter) |f| {
+            if (!is_unnamed_test and std.mem.indexOf(u8, t.name, f) == null) {
+                continue;
+            }
+        }
+
+        const friendly_name = blk: {
+            const name = t.name;
+            var it = std.mem.splitScalar(u8, name, '.');
+            while (it.next()) |value| {
+                if (std.mem.eql(u8, value, "test")) {
+                    const rest = it.rest();
+                    break :blk if (rest.len > 0) rest else name;
+                }
+            }
+            break :blk name;
+        };
+
+        current_test = friendly_name;
+        std.testing.allocator_instance = .{};
+        const result = t.func();
+        current_test = null;
+
+        const ns_taken = slowest.endTiming(friendly_name);
+
+        if (std.testing.allocator_instance.deinit() == .leak) {
+            leak += 1;
+            printer.status(.fail, "\n{s}\n\"{s}\" - Memory Leak\n{s}\n", .{ BORDER, friendly_name, BORDER });
+        }
+
+        if (result) |_| {
+            pass += 1;
+        } else |err| switch (err) {
+            error.SkipZigTest => {
+                skip += 1;
+                status = .skip;
+            },
+            else => {
+                status = .fail;
+                fail += 1;
+                printer.status(.fail, "\n{s}\n\"{s}\" - {s}\n{s}\n", .{ BORDER, friendly_name, @errorName(err), BORDER });
+                if (@errorReturnTrace()) |trace| {
+                    std.debug.dumpStackTrace(trace.*);
+                }
+                if (env.fail_first) {
+                    break;
+                }
+            },
+        }
+
+        if (env.verbose) {
+            const ms = @as(f64, @floatFromInt(ns_taken)) / 1_000_000.0;
+            printer.status(status, "{s} ({d:.2}ms)\n", .{ friendly_name, ms });
+        } else {
+            printer.status(status, ".", .{});
+        }
+    }
+
+    const total_tests = pass + fail;
+    const status = if (fail == 0) Status.pass else Status.fail;
+    printer.status(status, "\n{d} of {d} test{s} passed\n", .{ pass, total_tests, if (total_tests != 1) "s" else "" });
+    if (skip > 0) {
+        printer.status(.skip, "{d} test{s} skipped\n", .{ skip, if (skip != 1) "s" else "" });
+    }
+    if (leak > 0) {
+        printer.status(.fail, "{d} test{s} leaked\n", .{ leak, if (leak != 1) "s" else "" });
+    }
+    printer.fmt("\n", .{});
+    try slowest.display(printer);
+    printer.fmt("\n", .{});
+    std.posix.exit(if (fail == 0) 0 else 1);
+}
+
+const Printer = struct {
+    out: std.fs.File.Writer,
+
+    fn init() Printer {
+        return .{
+            .out = std.io.getStdErr().writer(),
+        };
+    }
+
+    fn fmt(self: Printer, comptime format: []const u8, args: anytype) void {
+        std.fmt.format(self.out, format, args) catch unreachable;
+    }
+
+    fn status(self: Printer, s: Status, comptime format: []const u8, args: anytype) void {
+        const color = switch (s) {
+            .pass => "\x1b[32m",
+            .fail => "\x1b[31m",
+            .skip => "\x1b[33m",
+            else => "",
+        };
+        const out = self.out;
+        out.writeAll(color) catch @panic("writeAll failed?!");
+        std.fmt.format(out, format, args) catch @panic("std.fmt.format failed?!");
+        self.fmt("\x1b[0m", .{});
+    }
+};
+
+const Status = enum {
+    pass,
+    fail,
+    skip,
+    text,
+};
+
+const SlowTracker = struct {
+    const SlowestQueue = std.PriorityDequeue(TestInfo, void, compareTiming);
+    max: usize,
+    slowest: SlowestQueue,
+    timer: std.time.Timer,
+
+    fn init(allocator: Allocator, count: u32) SlowTracker {
+        const timer = std.time.Timer.start() catch @panic("failed to start timer");
+        var slowest = SlowestQueue.init(allocator, {});
+        slowest.ensureTotalCapacity(count) catch @panic("OOM");
+        return .{
+            .max = count,
+            .timer = timer,
+            .slowest = slowest,
+        };
+    }
+
+    const TestInfo = struct {
+        ns: u64,
+        name: []const u8,
+    };
+
+    fn deinit(self: SlowTracker) void {
+        self.slowest.deinit();
+    }
+
+    fn startTiming(self: *SlowTracker) void {
+        self.timer.reset();
+    }
+
+    fn endTiming(self: *SlowTracker, test_name: []const u8) u64 {
+        var timer = self.timer;
+        const ns = timer.lap();
+
+        var slowest = &self.slowest;
+
+        if (slowest.count() < self.max) {
+            // Capacity is fixed to the # of slow tests we want to track
+            // If we've tracked fewer tests than this capacity, than always add
+            slowest.add(TestInfo{ .ns = ns, .name = test_name }) catch @panic("failed to track test timing");
+            return ns;
+        }
+
+        {
+            // Optimization to avoid shifting the dequeue for the common case
+            // where the test isn't one of our slowest.
+            const fastest_of_the_slow = slowest.peekMin() orelse unreachable;
+            if (fastest_of_the_slow.ns > ns) {
+                // the test was faster than our fastest slow test, don't add
+                return ns;
+            }
+        }
+
+        // the previous fastest of our slow tests, has been pushed off.
+        _ = slowest.removeMin();
+        slowest.add(TestInfo{ .ns = ns, .name = test_name }) catch @panic("failed to track test timing");
+        return ns;
+    }
+
+    fn display(self: *SlowTracker, printer: Printer) !void {
+        var slowest = self.slowest;
+        const count = slowest.count();
+        printer.fmt("Slowest {d} test{s}: \n", .{ count, if (count != 1) "s" else "" });
+        while (slowest.removeMinOrNull()) |info| {
+            const ms = @as(f64, @floatFromInt(info.ns)) / 1_000_000.0;
+            printer.fmt("  {d:.2}ms\t{s}\n", .{ ms, info.name });
+        }
+    }
+
+    fn compareTiming(context: void, a: TestInfo, b: TestInfo) std.math.Order {
+        _ = context;
+        return std.math.order(a.ns, b.ns);
+    }
+};
+
+const Env = struct {
+    verbose: bool,
+    fail_first: bool,
+    filter: ?[]const u8,
+
+    fn init(allocator: Allocator) Env {
+        return .{
+            .verbose = readEnvBool(allocator, "TEST_VERBOSE", true),
+            .fail_first = readEnvBool(allocator, "TEST_FAIL_FIRST", false),
+            .filter = readEnv(allocator, "TEST_FILTER"),
+        };
+    }
+
+    fn deinit(self: Env, allocator: Allocator) void {
+        if (self.filter) |f| {
+            allocator.free(f);
+        }
+    }
+
+    fn readEnv(allocator: Allocator, key: []const u8) ?[]const u8 {
+        const v = std.process.getEnvVarOwned(allocator, key) catch |err| {
+            if (err == error.EnvironmentVariableNotFound) {
+                return null;
+            }
+            std.log.warn("failed to get env var {s} due to err {}", .{ key, err });
+            return null;
+        };
+        return v;
+    }
+
+    fn readEnvBool(allocator: Allocator, key: []const u8, deflt: bool) bool {
+        const value = readEnv(allocator, key) orelse return deflt;
+        defer allocator.free(value);
+        return std.ascii.eqlIgnoreCase(value, "true");
+    }
+};
+
+fn isUnnamed(t: std.builtin.TestFn) bool {
+    const marker = ".test_";
+    const test_name = t.name;
+    const index = std.mem.indexOf(u8, test_name, marker) orelse return false;
+    _ = std.fmt.parseInt(u32, test_name[index + marker.len ..], 10) catch return false;
+    return true;
+}
+
+fn serverHTTP(listener: *std.net.Server) !void {
+    var read_buffer: [1024]u8 = undefined;
+    ACCEPT: while (true) {
+        var conn = try listener.accept();
+        defer conn.stream.close();
+        var server = std.http.Server.init(conn, &read_buffer);
+
+        while (server.state == .ready) {
+            var request = server.receiveHead() catch |err| switch (err) {
+                error.HttpConnectionClosing => continue :ACCEPT,
+                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 writeResponse(&request, .{
+                    .body = "Hello!",
+                });
+            }
+        }
+    }
+}
+
+const Response = struct {
+    body: []const u8 = "",
+    status: std.http.Status = .ok,
+};
+
+fn writeResponse(req: *std.http.Server.Request, res: Response) !void {
+    try req.respond(res.body, .{ .status = res.status });
+}
+
+test {
+    std.testing.refAllDecls(@import("url/query.zig"));
+    std.testing.refAllDecls(@import("browser/dump.zig"));
+    std.testing.refAllDecls(@import("browser/loader.zig"));
+    std.testing.refAllDecls(@import("browser/mime.zig"));
+    std.testing.refAllDecls(@import("cdp/msg.zig"));
+    std.testing.refAllDecls(@import("css/css.zig"));
+    std.testing.refAllDecls(@import("css/libdom_test.zig"));
+    std.testing.refAllDecls(@import("css/match_test.zig"));
+    std.testing.refAllDecls(@import("css/parser.zig"));
+    std.testing.refAllDecls(@import("generate.zig"));
+    std.testing.refAllDecls(@import("http/Client.zig"));
+    std.testing.refAllDecls(@import("msg.zig"));
+    std.testing.refAllDecls(@import("storage/storage.zig"));
+    std.testing.refAllDecls(@import("iterator/iterator.zig"));
+}
diff --git a/src/url/query.zig b/src/url/query.zig
index 3b1f877f..5defb288 100644
--- a/src/url/query.zig
+++ b/src/url/query.zig
@@ -62,6 +62,7 @@ pub const Values = struct {
     // append by taking the ownership of the key and the value
     fn appendOwned(self: *Values, k: []const u8, v: []const u8) !void {
         if (self.map.getPtr(k)) |list| {
+            self.alloc.free(k);
             return try list.append(self.alloc, v);
         }