zig build test --json to get duration/memory stats

src/browser/dom/attribute.zig

@@ -67,7 +67,7 @@ pub const Attr = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.Attribute" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/character_data.zig

@@ -103,7 +103,7 @@ pub const CharacterData = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.CharacterData" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/comment.zig

@@ -41,7 +41,7 @@ pub const Comment = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.Comment" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/document.zig

@@ -254,7 +254,7 @@ pub const Document = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.Document" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/document_fragment.zig

@@ -37,7 +37,7 @@ pub const DocumentFragment = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.DocumentFragment" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/element.zig

@@ -361,7 +361,7 @@ pub const Element = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.Element" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/event_target.zig

@@ -115,7 +115,7 @@ pub const EventTarget = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.EventTarget" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/exceptions.zig

@@ -167,7 +167,7 @@ pub const DOMException = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.Exception" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     const err = "Failed to execute 'appendChild' on 'Node': The new child element contains the parent.";

src/browser/dom/html_collection.zig

@@ -468,7 +468,7 @@ pub const HTMLCollection = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.HTMLCollection" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/implementation.zig

@@ -88,7 +88,7 @@ pub const DOMImplementation = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.Implementation" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/mutation_observer.zig

@@ -346,7 +346,7 @@ const EventHandler = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.MutationObserver" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/namednodemap.zig

@@ -77,7 +77,7 @@ pub const NamedNodeMap = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.NamedNodeMap" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/node.zig

@@ -408,7 +408,7 @@ pub const Node = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.node" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.exec(

src/browser/dom/nodelist.zig

@@ -171,7 +171,7 @@ pub const NodeList = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.NodeList" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/processing_instruction.zig

@@ -49,7 +49,7 @@ pub const ProcessingInstruction = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.ProcessingInstruction" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/text.zig

@@ -62,7 +62,7 @@ pub const Text = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.Text" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/dom/token_list.zig

@@ -107,7 +107,7 @@ pub const DOMTokenList = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.DOM.TokenList" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/events/event.zig

@@ -147,7 +147,7 @@ pub const EventHandler = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.Event" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/html/document.zig

@@ -219,7 +219,7 @@ pub const HTMLDocument = struct {
 const testing = @import("../../testing.zig");
 
 test "Browser.HTML.Document" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/html/elements.zig

@@ -913,7 +913,7 @@ pub fn toInterface(comptime T: type, e: *parser.Element) !T {
 
 const testing = @import("../../testing.zig");
 test "Browser.HTML.Element" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/html/history.zig

@@ -98,7 +98,7 @@ pub const History = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.HTML.History" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/html/location.zig

@@ -97,7 +97,7 @@ pub const Location = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.HTML.Location" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/html/navigator.zig

@@ -89,7 +89,7 @@ pub const Navigator = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.HTML.Navigator" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/polyfill/fetch.zig

@@ -14,7 +14,7 @@ pub const source = @embedFile("fetch.js");
 
 const testing = @import("../../testing.zig");
 test "Browser.fetch" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try @import("polyfill.zig").load(testing.allocator, runner.executor);

src/browser/storage/storage.zig

@@ -217,7 +217,7 @@ pub const Bottle = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.Storage.LocalStorage" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/url/url.zig

@@ -265,7 +265,7 @@ pub const URLSearchParams = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.URL" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/xhr/progress_event.zig

@@ -69,7 +69,7 @@ pub const ProgressEvent = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.XHR.ProgressEvent" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/xhr/xhr.zig

@@ -818,7 +818,7 @@ pub const XMLHttpRequest = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.XHR.XMLHttpRequest" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/browser/xmlserializer/xmlserializer.zig

@@ -47,7 +47,7 @@ pub const XMLSerializer = struct {
 
 const testing = @import("../../testing.zig");
 test "Browser.XMLSerializer" {
-    var runner = try testing.jsRunner(testing.allocator, .{});
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
     defer runner.deinit();
 
     try runner.testCases(&.{

src/test_runner.zig

@@ -34,6 +34,9 @@ pub const std_options = std.Options{
     .side_channels_mitigations = .none,
 };
 
+pub var js_runner_duration: usize = 0;
+pub var tracking_allocator = TrackingAllocator.init(std.testing.allocator);
+
 pub fn main() !void {
     var mem: [8192]u8 = undefined;
     var fba = std.heap.FixedBufferAllocator.init(&mem);
@@ -171,27 +174,28 @@ pub fn main() !void {
 
     // TODO: at the very least, `browser` should return real stats
     if (json_stats) {
+        const stats = tracking_allocator.stats();
         try std.json.stringify(&.{
             .{ .name = "browser", .bench = .{
-                .duration = 3180096049,
-                .alloc_nb = 6,
-                .realloc_nb = 278,
-                .alloc_size = 24711226,
+                .duration = js_runner_duration,
+                .alloc_nb = stats.allocation_count,
+                .realloc_nb = stats.reallocation_count,
+                .alloc_size = stats.allocated_bytes,
             } },
             .{ .name = "libdom", .bench = .{
-                .duration = 3180096049,
+                .duration = js_runner_duration,
                 .alloc_nb = 0,
                 .realloc_nb = 0,
                 .alloc_size = 0,
             } },
             .{ .name = "v8", .bench = .{
-                .duration = 3180096049,
+                .duration = js_runner_duration,
                 .alloc_nb = 0,
                 .realloc_nb = 0,
                 .alloc_size = 0,
             } },
             .{ .name = "main", .bench = .{
-                .duration = 3180096049,
+                .duration = js_runner_duration,
                 .alloc_nb = 0,
                 .realloc_nb = 0,
                 .alloc_size = 0,
@@ -375,3 +379,93 @@ fn isSetup(t: std.builtin.TestFn) bool {
 fn isTeardown(t: std.builtin.TestFn) bool {
     return std.mem.endsWith(u8, t.name, "tests:afterAll");
 }
+
+pub const TrackingAllocator = struct {
+    parent_allocator: Allocator,
+    free_count: usize = 0,
+    allocated_bytes: usize = 0,
+    allocation_count: usize = 0,
+    reallocation_count: usize = 0,
+
+    const Stats = struct {
+        allocated_bytes: usize,
+        allocation_count: usize,
+        reallocation_count: usize,
+    };
+
+    fn init(parent_allocator: Allocator) TrackingAllocator {
+        return .{
+            .parent_allocator = parent_allocator,
+        };
+    }
+
+    pub fn stats(self: *const TrackingAllocator) Stats {
+        return .{
+            .allocated_bytes = self.allocated_bytes,
+            .allocation_count = self.allocation_count,
+            .reallocation_count = self.reallocation_count,
+        };
+    }
+
+    pub fn allocator(self: *TrackingAllocator) Allocator {
+        return .{
+            .ptr = self,
+            .vtable = &.{
+                .alloc = alloc,
+                .resize = resize,
+                .free = free,
+                .remap = remap,
+            }
+        };
+    }
+
+    fn alloc(
+        ctx: *anyopaque,
+        len: usize,
+        alignment: std.mem.Alignment,
+        return_address: usize,
+    ) ?[*]u8 {
+        const self: *TrackingAllocator = @ptrCast(@alignCast(ctx));
+        const result = self.parent_allocator.rawAlloc(len, alignment, return_address);
+        self.allocation_count += 1;
+        self.allocated_bytes += len;
+        return result;
+    }
+
+    fn resize(
+        ctx: *anyopaque,
+        old_mem: []u8,
+        alignment: std.mem.Alignment,
+        new_len: usize,
+        ra: usize,
+    ) bool {
+        const self: *TrackingAllocator = @ptrCast(@alignCast(ctx));
+        const result = self.parent_allocator.rawResize(old_mem, alignment, new_len, ra);
+        self.reallocation_count += 1; // TODO: only if result is not null?
+        return result;
+    }
+
+    fn free(
+        ctx: *anyopaque,
+        old_mem: []u8,
+        alignment: std.mem.Alignment,
+        ra: usize,
+    ) void {
+        const self: *TrackingAllocator = @ptrCast(@alignCast(ctx));
+        self.parent_allocator.rawFree(old_mem, alignment, ra);
+        self.free_count += 1;
+    }
+
+    fn remap(
+        ctx: *anyopaque,
+        memory: []u8,
+        alignment: std.mem.Alignment,
+        new_len: usize,
+        ret_addr: usize,
+    ) ?[*]u8 {
+        const self: *TrackingAllocator = @ptrCast(@alignCast(ctx));
+        const result = self.parent_allocator.rawRemap(memory, alignment, new_len, ret_addr);
+        self.reallocation_count += 1; // TODO: only if result is not null?
+        return result;
+    }
+};

src/testing.zig

@@ -351,6 +351,7 @@ fn isJsonValue(a: std.json.Value, b: std.json.Value) bool {
     }
 }
 
+pub const tracking_allocator = @import("root").tracking_allocator.allocator();
 pub const JsRunner = struct {
     const URL = @import("url.zig").URL;
     const Env = @import("browser/env.zig").Env;
@@ -443,6 +444,8 @@ pub const JsRunner = struct {
     const RunOpts = struct {};
     pub const Case = std.meta.Tuple(&.{ []const u8, []const u8 });
     pub fn testCases(self: *JsRunner, cases: []const Case, _: RunOpts) !void {
+        const start = try std.time.Instant.now();
+
         for (cases, 0..) |case, i| {
             var try_catch: Env.TryCatch = undefined;
             try_catch.init(self.executor);
@@ -455,6 +458,7 @@ pub const JsRunner = struct {
                 return err;
             };
             try self.loop.run();
+            @import("root").js_runner_duration += std.time.Instant.since(try std.time.Instant.now(), start);
 
             const actual = try value.toString(self.arena);
             if (std.mem.eql(u8, case.@"1", actual) == false) {