feat: offer non-travelling applicant choice only on selected travels

tests/BusProNet/Model/TravelTest.php

@@ -134,6 +134,27 @@ class TravelTest extends TestCase
         $this->assertFalse($travel->hasSelectionId(1473));
     }
 
+    public function testAllowsNonTravellingApplicantWithSelection1488(): void
+    {
+        $travel = new Travel();
+        $travel->selectionGroups = [
+            10 => $this->createSelectionGroup(10, [2001, 1488]),
+        ];
+
+        $this->assertTrue($travel->allowsNonTravellingApplicant());
+    }
+
+    public function testDoesNotAllowNonTravellingApplicantWithoutSelection1488(): void
+    {
+        $travel = new Travel();
+        $travel->selectionGroups = [
+            10 => $this->createSelectionGroup(10, [1473, 1475]),
+        ];
+
+        $this->assertFalse($travel->allowsNonTravellingApplicant());
+        $this->assertFalse((new Travel())->allowsNonTravellingApplicant(), 'A travel without any selections');
+    }
+
     /**
      * @param list<int> $selectionIds
      */