Add a timeout helper class

That is added to isolate the timeout 'business' rules are implemented
correctly. And make them testable.

src/Service/TimeoutHelper.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types = 1);
+
+/**
+ * Copyright 2024 SURFnet B.V.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Surfnet\Tiqr\Service;
+
+class TimeoutHelper
+{
+    public static function isTimedOut(
+        int $currentTime,
+        int $startedAt,
+        int $timeoutInSeconds,
+        int $offset
+    ) : bool {
+        $timeoutAt = $startedAt - $offset;
+        return ($currentTime - $timeoutAt) >= $timeoutInSeconds;
+    }
+}

tests/Unit/TimeoutHelperTest.php

@@ -0,0 +1,57 @@
+<?php
+/**
+ * Copyright 2024 SURFnet B.V.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Unit;
+
+use PHPUnit\Framework\TestCase;
+use Surfnet\Tiqr\Service\TimeoutHelper;
+
+class TimeoutHelperTest extends TestCase
+{
+    /**
+     * @dataProvider provideTimeoutExpectations
+     */
+    public function test_timeout_reached(
+        bool $expectation,
+        int $currentTime,
+        int $startedAt,
+        int $timeoutInSeconds,
+        int $offset
+    ): void{
+        $isTimedOut = TimeoutHelper::isTimedOut(
+            $currentTime,
+            $startedAt,
+            $timeoutInSeconds,
+            $offset,
+        );
+        self::assertEquals($expectation, $isTimedOut);
+    }
+
+    public function provideTimeoutExpectations(): array
+    {
+        return [
+            // Timed out expectations
+            'way over time' => [true, 1000, 0, 300, 2], // 100 seconds ago the user started the clock
+            'just over time' => [true, 303, 0, 300, 2], // 5 seconds over timeout time
+            'timeout due to offset - 1' => [true, 298, 0, 300, 2], // the offset is reached
+            'timeout due to offset - 2' => [true, 299, 0, 300, 2], // the offset is reached
+            // In time expectations
+            'very much in time' => [false, 0, 0, 300, 2], // 298 seconds to go before reaching timeout
+            'just in time' => [false, 297, 0, 300, 2], // last second before reaching timeout
+        ];
+    }
+}