move test imports to main.zig, remove test_root.zig

build.zig

···
     const run_step = b.step("run", "Run the feed server");
     run_step.dependOn(&run_cmd.step);
 
-    // tests
+    // tests - use main.zig as root, tests in all imported modules run automatically
     const tests = b.addTest(.{
         .root_module = b.createModule(.{
-            .root_source_file = b.path("src/test_root.zig"),
+            .root_source_file = b.path("src/main.zig"),
             .target = target,
             .optimize = optimize,
             .imports = &.{
+                .{ .name = "websocket", .module = websocket.module("websocket") },
+                .{ .name = "zqlite", .module = zqlite.module("zqlite") },
                 .{ .name = "zat", .module = zat.module("zat") },
             },
         }),
     });
+    tests.linkLibC();
 
     const run_tests = b.addRunArtifact(tests);
     const test_step = b.step("test", "Run unit tests");

src/main.zig

···
     try posix.setsockopt(fd, posix.SOL.SOCKET, posix.SO.RCVTIMEO, &timeout);
     try posix.setsockopt(fd, posix.SOL.SOCKET, posix.SO.SNDTIMEO, &timeout);
 }
+
+test {
+    _ = @import("feed/filter.zig");
+    _ = @import("server/stats.zig");
+}

src/test_root.zig

···
-// test root - imports modules to run their tests
-
-test {
-    _ = @import("feed/filter.zig");
-    _ = @import("server/stats.zig");
-}