diff --git a/src/Client/Caster/Trace.php b/src/Client/Caster/Trace.php
index 7b936bd2..9be5c575 100644
--- a/src/Client/Caster/Trace.php
+++ b/src/Client/Caster/Trace.php
@@ -15,7 +15,7 @@ final class Trace
     /**
      * @param int<0, max> $number The tick number.
      * @param float $delta The time delta between the current and previous tick.
-     * @param int $memory The memory usage.
+     * @param int<0, max> $memory The memory usage.
      * @param list<array{
      *     function: non-empty-string,
      *     line?: int,
@@ -42,7 +42,7 @@ public function __toString(): string
             $delta < 0.01 => \sprintf('+%.2fms', $delta * 1000),
             $delta < 1 => \sprintf('+%.1fms', ($delta * 1000)),
             $delta < 10 => \sprintf('+%.2fs', $delta),
-            $delta < 60 => \sprintf('+%.3fs', $delta),
+            $delta < 60 => \sprintf('+%.1fs', $delta),
             default => \sprintf('+%dm %ds', (int) $delta % 60, (int) $delta % 60),
         };
 
diff --git a/src/functions.php b/src/functions.php
index 0bb74ce9..2776bf89 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -77,6 +77,8 @@ function tr(mixed ...$values): mixed
      * When no arguments passed, it works like {@see tr()}.
      *
      * @param mixed ...$values
+     *
+     * @codeCoverageIgnore
      */
     function td(mixed ...$values): never
     {
diff --git a/tests/Unit/Client/Caster/TraceFileTest.php b/tests/Unit/Client/Caster/TraceFileTest.php
new file mode 100644
index 00000000..14012a0f
--- /dev/null
+++ b/tests/Unit/Client/Caster/TraceFileTest.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Buggregator\Trap\Tests\Unit\Client\Caster;
+
+use PHPUnit\Framework\TestCase;
+
+final class TraceFileTest extends TestCase
+{
+    public function testToString(): void
+    {
+        $traceFile = new \Buggregator\Trap\Client\Caster\TraceFile([
+            'function' => 'foo',
+            'line' => 42,
+            'file' => '/path/to/file.php',
+            'class' => 'Foo',
+            'type' => '->',
+            'args' => ['bar'],
+        ]);
+
+        self::assertSame('file.php:42', (string) $traceFile);
+    }
+
+    public function testToStringWithoutFile(): void
+    {
+        $traceFile = new \Buggregator\Trap\Client\Caster\TraceFile([
+            'function' => 'foo',
+        ]);
+
+        self::assertSame('<internal>', (string) $traceFile);
+    }
+
+    public function testToStringWithoutLine(): void
+    {
+        $traceFile = new \Buggregator\Trap\Client\Caster\TraceFile([
+            'function' => 'foo',
+            'file' => '/path/to/file.php',
+        ]);
+
+        self::assertSame('<internal>', (string) $traceFile);
+    }
+}
diff --git a/tests/Unit/Client/Caster/TraceTest.php b/tests/Unit/Client/Caster/TraceTest.php
new file mode 100644
index 00000000..1b822684
--- /dev/null
+++ b/tests/Unit/Client/Caster/TraceTest.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Buggregator\Trap\Tests\Unit\Client\Caster;
+
+use Buggregator\Trap\Client\Caster\Trace;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+final class TraceTest extends TestCase
+{
+    public static function provideToString(): iterable
+    {
+        yield [0, 0.0, 102400, 'Trace #0  -.---  0.10M'];
+        yield [5, 0.000123, 123456, 'Trace #5  +0.123ms  0.12M'];
+        yield [4, 0.00123, 123456, 'Trace #4  +1.23ms  0.12M'];
+        yield [3, 0.123, 123456, 'Trace #3  +123.0ms  0.12M'];
+        yield [2, 1.23, 123456, 'Trace #2  +1.23s  0.12M'];
+        yield [1, 42.3, 123456, 'Trace #1  +42.3s  0.12M'];
+        yield [42, 10050.0, 0, 'Trace #42  +30m 30s  0.00M'];
+    }
+
+    /**
+     * @param int<0, max> $number
+     * @param int<0, max> $memory
+     * @param non-empty-string $result
+     */
+    #[DataProvider('provideToString')]
+    public function testToString(int $number, float $delta, int $memory, string $result): void
+    {
+        $trace = new Trace(
+            number: $number,
+            delta: $delta,
+            memory: $memory,
+            stack: [
+                [
+                    'function' => 'foo',
+                    'line' => 42,
+                    'file' => '/path/to/file.php',
+                    'class' => 'Foo',
+                    'type' => '->',
+                    'args' => ['bar'],
+                ],
+                [
+                    'function' => 'bar',
+                    'line' => 23,
+                    'file' => '/path/to/file.php',
+                    'class' => 'Bar',
+                    'type' => '::',
+                    'args' => ['baz'],
+                ],
+            ],
+        );
+
+        self::assertSame($result, (string) $trace);
+    }
+}