Update REST API test

src/world.zig

@@ -303,11 +303,10 @@ pub fn World(comptime ctx: anytype) type {
     };
 }
 
-test "World REST API" {
-    const expect = @import("./test/expect.zig");
-    const alloc = std.testing.allocator;
+const expect = @import("./test/expect.zig");
 
-    flecszigble.init(alloc);
+test "World REST API" {
+    flecszigble.init(std.testing.allocator);
     var world = try World(void).init();
     defer world.deinit();
     try world.enableRest(42666);
@@ -318,16 +317,25 @@ test "World REST API" {
         }
     };
 
+    const alloc = std.testing.allocator;
     var thread = try std.Thread.spawn(.{ .allocator = alloc }, Runner.run, .{world});
     defer thread.join();
 
+    // Unsure if compiling or running this takes a really long time, but this
+    // test using `http.Client` adds about 10s to the test run time. Oh well.
     const url = "http://localhost:42666/entity/flecs/core/World";
     var client = std.http.Client{ .allocator = alloc };
     defer client.deinit();
-    var result = try client.fetch(alloc, .{ .location = .{ .url = url } });
-    defer result.deinit();
 
-    try expect.equalStrings("{\"path\":\"flecs.core.World\", \"ids\":[]}", result.body);
+    var response = std.ArrayList(u8).init(alloc);
+    defer response.deinit();
+    const result = try client.fetch(.{
+        .location = .{ .url = url },
+        .response_storage = .{ .dynamic = &response },
+    });
+
+    try expect.equal(std.http.Status.ok, result.status);
+    try expect.equalStrings("{\"path\":\"flecs.core.World\", \"ids\":[]}", response.items);
 
     world.quit();
 }