"Empty data set provided by data provider"

[staabm]

Starting with PHPUnit 10 a dataprovider is not allowed to provide a empty array.

<?php

use PHPUnit\Framework\Attributes\DataProvider;

class BarTest extends PHPUnit\Framework\TestCase
{
    /**
     * @dataProvider provideData
     */
    #[DataProvider("provideData")]
    public function testBar() {
        self::assertTrue(true);
    }

    static public function provideData(): iterable {
        return [];
    }
}

real world example in phpstan-doctrine

---

PHPUnit 9 skips and warns

➜  phpunit git:(9.6) ✗ php phpunit BarTest.php
PHPUnit 9.6.29-15-g3ee3d102e by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.27
Configuration: /Users/staabm/workspace/phpunit/phpunit.xml

S                                                                   1 / 1 (100%)

Time: 00:00.002, Memory: 6.00 MB

There was 1 skipped test:

1) BarTest::testBar
Test for BarTest::testBar skipped by data provider
PHPUnit\Framework\SkippedTestError: <no message>
/Users/staabm/workspace/phpunit/src/Util/Annotation/DocBlock.php:285
/Users/staabm/workspace/phpunit/src/Util/Test.php:329
/Users/staabm/workspace/phpunit/src/Framework/TestBuilder.php:72
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:891
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:232
/Users/staabm/workspace/phpunit/src/Runner/BaseTestRunner.php:133
/Users/staabm/workspace/phpunit/src/TextUI/Command.php:121
/Users/staabm/workspace/phpunit/src/TextUI/Command.php:99

/Users/staabm/workspace/phpunit/src/Framework/Assert.php:2895
/Users/staabm/workspace/phpunit/src/Framework/SkippedTestCase.php:66
/Users/staabm/workspace/phpunit/src/Framework/TestCase.php:1223
/Users/staabm/workspace/phpunit/src/Framework/TestResult.php:729
/Users/staabm/workspace/phpunit/src/Framework/TestCase.php:973
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:685
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:685
/Users/staabm/workspace/phpunit/src/TextUI/TestRunner.php:651
/Users/staabm/workspace/phpunit/src/TextUI/Command.php:146
/Users/staabm/workspace/phpunit/src/TextUI/Command.php:99

OK, but incomplete, skipped, or risky tests!
Tests: 1, Assertions: 0, Skipped: 1.

---

PHPUnit 10 errors

➜  phpunit git:(10.5) ✗ php phpunit BarTest.php
PHPUnit 10.5.58-15-gc66b7d664 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.27
Configuration: /Users/staabm/workspace/phpunit/phpunit.xml

There was 1 PHPUnit error:

1) BarTest::testBar
The data provider specified for BarTest::testBar is invalid
Empty data set provided by data provider
/Users/staabm/workspace/phpunit/src/Metadata/Api/DataProvider.php:76
/Users/staabm/workspace/phpunit/src/Framework/TestBuilder.php:44
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:511
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:139
/Users/staabm/workspace/phpunit/src/TextUI/Configuration/TestSuiteBuilder.php:122
/Users/staabm/workspace/phpunit/src/TextUI/Configuration/TestSuiteBuilder.php:58
/Users/staabm/workspace/phpunit/src/TextUI/Application.php:394
/Users/staabm/workspace/phpunit/src/TextUI/Application.php:114

/Users/staabm/workspace/phpunit/BarTest.php:11

--

There was 1 PHPUnit test runner warning:

1) No tests found in class "BarTest".

No tests executed!

---

PHPUnit11,12,13 errors

➜  phpunit git:(11.5) ✗ php phpunit BarTest.php
PHPUnit 11.5.42-27-g32e5fd8bc by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.27
Configuration: /Users/staabm/workspace/phpunit/phpunit.xml

There was 1 PHPUnit error:

1) BarTest::testBar
The data provider specified for BarTest::testBar is invalid
Empty data set provided by data provider
/Users/staabm/workspace/phpunit/src/Metadata/Api/DataProvider.php:75
/Users/staabm/workspace/phpunit/src/Framework/TestBuilder.php:47
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:508
/Users/staabm/workspace/phpunit/src/Framework/TestSuite.php:109
/Users/staabm/workspace/phpunit/src/TextUI/Configuration/TestSuiteBuilder.php:121
/Users/staabm/workspace/phpunit/src/TextUI/Configuration/TestSuiteBuilder.php:58
/Users/staabm/workspace/phpunit/src/TextUI/Application.php:412
/Users/staabm/workspace/phpunit/src/TextUI/Application.php:182

/Users/staabm/workspace/phpunit/BarTest.php:11

--

There was 1 PHPUnit test runner warning:

1) No tests found in class "BarTest".

No tests executed!