Closes #6300

Author: sebastianbergmann

ChangeLog-10.5.md

@@ -2,6 +2,12 @@
 
 All notable changes of the PHPUnit 10.5 release series are documented in this file using the [Keep a CHANGELOG](https://keepachangelog.com/) principles.
 
+## [10.5.50] - 2025-MM-DD
+
+### Changed
+
+* [#6300](https://github.com/sebastianbergmann/phpunit/issues/6300): Emit warning when the name of a data provider method begins with `test`
+
 ## [10.5.49] - 2025-08-09
 
 ### Added
@@ -446,6 +452,7 @@ All notable changes of the PHPUnit 10.5 release series are documented in this fi
 
 * [#5563](https://github.com/sebastianbergmann/phpunit/issues/5563): `createMockForIntersectionOfInterfaces()` does not automatically register mock object for expectation verification
 
+[10.5.50]: https://github.com/sebastianbergmann/phpunit/compare/10.5.49...10.5
 [10.5.49]: https://github.com/sebastianbergmann/phpunit/compare/10.5.48...10.5.49
 [10.5.48]: https://github.com/sebastianbergmann/phpunit/compare/10.5.47...10.5.48
 [10.5.47]: https://github.com/sebastianbergmann/phpunit/compare/10.5.46...10.5.47

src/Metadata/Api/DataProvider.php

@@ -15,6 +15,7 @@
 use function assert;
 use function explode;
 use function get_debug_type;
+use function is_a;
 use function is_array;
 use function is_int;
 use function is_string;
@@ -26,6 +27,7 @@
 use function rtrim;
 use function sprintf;
 use function str_replace;
+use function str_starts_with;
 use function strlen;
 use function substr;
 use function trim;
@@ -34,6 +36,7 @@
 use PHPUnit\Event\TestData\MoreThanOneDataSetFromDataProviderException;
 use PHPUnit\Event\TestData\TestDataCollection;
 use PHPUnit\Framework\InvalidDataProviderException;
+use PHPUnit\Framework\TestCase;
 use PHPUnit\Metadata\DataProvider as DataProviderMetadata;
 use PHPUnit\Metadata\MetadataCollection;
 use PHPUnit\Metadata\Parser\Registry as MetadataRegistry;
@@ -106,6 +109,19 @@ private function dataProvidedByMethods(string $className, string $methodName, Me
         foreach ($dataProvider as $_dataProvider) {
             assert($_dataProvider instanceof DataProviderMetadata);
 
+            if (is_a($_dataProvider->className(), TestCase::class, true) &&
+                str_starts_with($_dataProvider->methodName(), 'test')) {
+                Event\Facade::emitter()->testRunnerTriggeredPhpunitWarning(
+                    sprintf(
+                        'The name of the data provider method %s::%s() used by test method %s::%s() begins with "test", therefore PHPUnit also treats it as a test method',
+                        $_dataProvider->className(),
+                        $_dataProvider->methodName(),
+                        $className,
+                        $methodName,
+                    ),
+                );
+            }
+
             $dataProviderMethod = new Event\Code\ClassMethod($_dataProvider->className(), $_dataProvider->methodName());
 
             Event\Facade::emitter()->dataProviderMethodCalled(

tests/_files/DataProviderMethodNameStartsWithTestTest.php

@@ -0,0 +1,27 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\TestFixture;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+final class DataProviderMethodNameStartsWithTestTest extends TestCase
+{
+    public static function testProvider(): array
+    {
+        return [[true]];
+    }
+
+    #[DataProvider('testProvider')]
+    public function testOne(bool $b): void
+    {
+        $this->assertTrue($b);
+    }
+}

tests/end-to-end/data-provider/warning-when-data-provider-method-name-begins-with-test.phpt

@@ -0,0 +1,42 @@
+--TEST--
+phpunit ../../_files/DataProviderMethodNameStartsWithTestTest.php
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = '--debug';
+$_SERVER['argv'][] = __DIR__ . '/../../_files/DataProviderMethodNameStartsWithTestTest.php';
+
+require_once __DIR__ . '/../../bootstrap.php';
+
+(new PHPUnit\TextUI\Application)->run($_SERVER['argv']);
+--EXPECTF--
+PHPUnit Started (PHPUnit %s using %s)
+Test Runner Configured
+Test Runner Triggered Warning (The name of the data provider method PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider() used by test method PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne() begins with "test", therefore PHPUnit also treats it as a test method)
+Data Provider Method Called (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider for test method PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne)
+Data Provider Method Finished for PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne:
+- PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider
+Test Suite Loaded (2 tests)
+Event Facade Sealed
+Test Runner Started
+Test Suite Sorted
+Test Runner Execution Started (2 tests)
+Test Suite Started (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest, 2 tests)
+Test Preparation Started (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider)
+Test Prepared (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider)
+Test Passed (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider)
+Test Considered Risky (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider)
+This test did not perform any assertions
+Test Finished (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testProvider)
+Test Suite Started (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne, 1 test)
+Test Preparation Started (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne#0)
+Test Prepared (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne#0)
+Assertion Succeeded (Constraint: is true, Value: true)
+Test Passed (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne#0)
+Test Finished (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne#0)
+Test Suite Finished (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest::testOne, 1 test)
+Test Suite Finished (PHPUnit\TestFixture\DataProviderMethodNameStartsWithTestTest, 2 tests)
+Test Runner Execution Finished
+Test Runner Finished
+PHPUnit Finished (Shell Exit Code: 1)