☁️VoltTest Cloud closed beta is now open—Join the waitlist
Skip to main content

Performance Assertions

Assert performance thresholds in your PHPUnit tests. All assertions are available on PerformanceTestCase via the VoltTestAssertions trait.

Success Rate​

assertVTSuccessful​

Assert that the success rate meets a minimum threshold.

$this->assertVTSuccessful($result);           // Default: 95%
$this->assertVTSuccessful($result, 99.0);     // Custom: 99%

assertVTErrorRate​

Assert that the error rate stays below a maximum threshold.

$this->assertVTErrorRate($result, 5.0);       // Max 5% errors
$this->assertVTErrorRate($result, 1.0);       // Max 1% errors

Response Times​

All response time assertions use milliseconds.

assertVTMaxResponseTime​

Assert that the maximum (slowest) response time doesn't exceed the threshold.

$this->assertVTMaxResponseTime($result, 5000);  // Max 5 seconds

assertVTAverageResponseTime​

$this->assertVTAverageResponseTime($result, 500);  // Avg under 500ms

assertVTMedianResponseTime​

$this->assertVTMedianResponseTime($result, 300);  // P50 under 300ms

assertVTP95ResponseTime​

$this->assertVTP95ResponseTime($result, 1000);  // P95 under 1 second

assertVTP99ResponseTime​

$this->assertVTP99ResponseTime($result, 2000);  // P99 under 2 seconds

assertVTMinResponseTime​

Assert that the minimum (fastest) response time is at least a given value. Useful for detecting suspiciously fast responses (e.g., cached/mocked responses when you expect real ones).

$this->assertVTMinResponseTime($result, 10);  // Min at least 10ms

Throughput​

assertVTMinimumRequests​

Assert that the total number of requests meets a minimum.

$this->assertVTMinimumRequests($result, 1000);  // At least 1000 total requests

assertVTMinimumRPS​

Assert a minimum requests-per-second throughput.

$this->assertVTMinimumRPS($result, 50);  // At least 50 req/s

assertVTMaximumRPS​

Assert a maximum requests-per-second. Useful for rate-limited endpoints.

$this->assertVTMaximumRPS($result, 100);  // No more than 100 req/s

Complete Example​

<?php

namespace Tests\Performance;

use App\VoltTests\ApiTest;
use VoltTest\Laravel\Testing\PerformanceTestCase;

class ApiPerformanceTest extends PerformanceTestCase
{
    public function test_api_meets_sla(): void
    {
        $result = $this->runVoltTest(new ApiTest(), [
            'virtual_users' => 50,
            'duration' => '2m',
        ]);

        // SLA: 99% success rate
        $this->assertVTSuccessful($result, 99.0);

        // SLA: P95 under 500ms
        $this->assertVTP95ResponseTime($result, 500);

        // SLA: P99 under 2 seconds
        $this->assertVTP99ResponseTime($result, 2000);

        // SLA: At least 100 requests per second
        $this->assertVTMinimumRPS($result, 100);

        // No suspiciously fast responses
        $this->assertVTMinResponseTime($result, 5);
    }
}

Assertion Reference​

AssertionParameterDescription
assertVTSuccessful($result, $min)float (default: 95.0)Success rate ≥ threshold
assertVTErrorRate($result, $max)floatError rate ≤ threshold
assertVTMinResponseTime($result, $ms)int (ms)Min response time ≥ threshold
assertVTMaxResponseTime($result, $ms)int (ms)Max response time ≤ threshold
assertVTAverageResponseTime($result, $ms)int (ms)Average ≤ threshold
assertVTMedianResponseTime($result, $ms)int (ms)Median (P50) ≤ threshold
assertVTP95ResponseTime($result, $ms)int (ms)P95 ≤ threshold
assertVTP99ResponseTime($result, $ms)int (ms)P99 ≤ threshold
assertVTMinimumRequests($result, $n)intTotal requests ≥ threshold
assertVTMinimumRPS($result, $rps)floatRequests/sec ≥ threshold
assertVTMaximumRPS($result, $rps)floatRequests/sec ≤ threshold