test(process): add listening resolver unit coverage

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

tests/php/Unit/Service/Process/ListeningPidResolverTest.php

@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 LibreCode coop and contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Libresign\Tests\Unit\Service\Process;
+
+use OCA\Libresign\Service\Process\ListeningPidResolver;
+use OCA\Libresign\Tests\Unit\TestCase;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+class ListeningPidResolverTest extends TestCase {
+	#[DataProvider('provideInvalidPorts')]
+	public function testFindListeningPidsRejectsInvalidPort(int $port): void {
+		$resolver = new ListeningPidResolver();
+
+		$this->expectException(\RuntimeException::class);
+		$this->expectExceptionMessage('Invalid port');
+
+		$resolver->findListeningPids($port);
+	}
+
+	/**
+	 * @return array<string, array{0: int}>
+	 */
+	public static function provideInvalidPorts(): array {
+		return [
+			'zero' => [0],
+			'negative' => [-1],
+		];
+	}
+
+	public function testFindListeningPidsMergesUniqueFromAvailableStrategies(): void {
+		$resolver = new class() extends ListeningPidResolver {
+			protected function findListeningPidsUsingSs(int $port): ?array {
+				return [100, 101];
+			}
+
+			protected function findListeningPidsUsingLsof(int $port): ?array {
+				return [101, 102];
+			}
+
+			protected function findListeningPidsUsingProc(int $port): ?array {
+				return [102, 103];
+			}
+		};
+
+		$actual = $resolver->findListeningPids(8888);
+		sort($actual);
+
+		$this->assertSame([100, 101, 102, 103], $actual);
+	}
+
+	public function testFindListeningPidsThrowsWhenNoStrategyIsAvailable(): void {
+		$resolver = new class() extends ListeningPidResolver {
+			protected function findListeningPidsUsingSs(int $port): ?array {
+				return null;
+			}
+
+			protected function findListeningPidsUsingLsof(int $port): ?array {
+				return null;
+			}
+
+			protected function findListeningPidsUsingProc(int $port): ?array {
+				return null;
+			}
+		};
+
+		$this->expectException(\RuntimeException::class);
+		$this->expectExceptionMessage('no strategy available');
+
+		$resolver->findListeningPids(8888);
+	}
+}