Ignore Deprecation Notice in PHPUnit 9?
Stefan Bogdanescu
Founder & Senior Architect · 2026-06-29
# Ignore Deprecation Notice in PHPUnit 9? Navigating Assertions and Evolution in Testing
As developers working within the dynamic Laravel ecosystem, we are constantly iterating with our tools. When frameworks like PHPUnit evolve, they introduce deprecation noticesâwarnings that signal upcoming changes or deprecated features that need updating. Running into these warnings during testing, especially when using specific assertion methods like `assertRegExp`, can be frustrating.
This post addresses a common scenario: how to handle deprecation warnings generated by PHPUnit 9 when using older assertion methods and what the best path forward is for modern Laravel testing practices.
## The Evolution of Assertions in PHPUnit
The warning you are seeing, specifically regarding `assertRegExp`, stems from PHPUnitâs ongoing effort to modernize its API. Deprecation notices are not just annoying; they serve as a roadmap, telling developers that certain methods will be removed in future versions (like PHPUnit 10).
The core issue is the transition from older, more concise assertions to newer, more explicit ones. For instance, assertions dealing with regular expressions have been refined for better type safety and clarity.
### The Recommended Refactor: Moving to Modern Assertions
Instead of attempting to suppress warningsâwhich is generally discouraged as it hides potential bugs or necessary code updatesâthe professional approach is to refactor the code to use the recommended alternatives. This ensures your tests remain robust, future-proof, and align with modern PHP standards.
For assertions involving regular expressions, PHPUnit now strongly recommends using `assertMatchesRegularExpression()` instead of the deprecated `assertRegExp()`.
Here is a side-by-side comparison illustrating the necessary refactoring:
```php
// Deprecated approach (Causes the warning)
public function testOldRegexAssertion($response)
{
$this->assertTrue(
$response->content === 'expected string',
"Content mismatch"
); // Example of a hypothetical old assertion structure
}
// Recommended modern approach
use PHPUnit\Framework\Assert;
public function testModernRegexAssertion($response)
{
$pattern = '/^some_prefix/m';
$this->assertTrue(
preg_match($pattern, $response->content),
"Content does not match the required pattern."
);
// Or using the specific PHPUnit assertion if available in your context
// assertMatchesRegularExpression($pattern, $response->content);
}
```
By adopting `assertMatchesRegularExpression()`, you are not just silencing a warning; you are writing code that is compatible with future versions of the framework. This commitment to quality mirrors the philosophy behind building solid applications, much like the principles emphasized in robust Laravel development patterns found on sites like [laravelcompany.com](https://laravelcompany.com).
## Suppressing Warnings: A Last Resort
While refactoring is the best solution, sometimes you might encounter legacy codebases or specific third-party packages where immediate refactoring is impractical. If you absolutely must suppress a warning for a very specific test case, you can utilize PHP's error handling mechanisms within your test file.
You can use the `@suppress` annotation on a method level to tell PHP to ignore errors thrown within that scope. However, this should be used sparingly:
```php
/**
* @suppress PHPUnit\Framework\Error\Warning
*/
public function testSpecificLegacyAssertion()
{
// Code that uses the deprecated assertRegExp()
$this->assertRegExp('/pattern/', $string);
}
```
**A Word of Caution:** Suppressing deprecation warnings should be treated as a temporary measure, not a permanent fix. It masks potential issues and prevents you from addressing code modernization, which is crucial when maintaining large applications built on frameworks like Laravel.
## Conclusion
The key takeaway here is that deprecation notices are signals for change. Instead of fighting the warning with suppression flags, developers should embrace the evolution by refactoring assertions to use modern equivalents, such as `assertMatchesRegularExpression()`. This practice leads to cleaner, more maintainable, and future-proof tests, aligning perfectly with the high standards expected in professional Laravel development. Always prioritize code quality over suppressing warnings.