mkdir /tmp/test
cd /tmp/test
cat <<'EOF' > test.php
<?php
class FooTest {
    function test() {
        $this->assertFalse( strpos( $haystack, $needle ) );
        $this->assertNotFalse( strpos( $haystack, $needle ) );
        $this->assertIsInt( strpos( $haystack, $needle ) );
    }
}
EOF
composer require mediawiki/mediawiki-codesniffer
vendor/bin/phpcbf --standard=vendor/mediawiki/mediawiki-codesniffer/MediaWiki/ruleset.xml test.php

<?php
class FooTest {
	function test() {
		$this->assertStringNotContainsString( $haystack, $needle );
		$this->assertStringContainsString( $haystack, $needle );
		$this->assertStringContainsString( $haystack, $needle );
	}
}

<?php
class FooTest {
	function test() {
		$this->assertStringNotContainsString( $needle, $haystack );
		$this->assertStringContainsString( $needle, $haystack );
		$this->assertStringContainsString( $needle, $haystack );
	}
}