diff --git a/lib/test_runner.zig b/lib/test_runner.zig
index 42fdf3bec735..0b7ee24fde65 100644
--- a/lib/test_runner.zig
+++ b/lib/test_runner.zig
@@ -1,3 +1,4 @@
+//! Default test runner for unit tests.
 const std = @import("std");
 const io = std.io;
 const builtin = @import("builtin");