chore: major code cleanup and type safety using phpstan

tests/BusProNet/Model/TravelTest.php

@@ -41,12 +41,12 @@ class TravelTest extends TestCase
         $travel->transportationServices = [$outboundPkw, $inboundPkw];
 
         $outboundResult = $travel->getTransportationServicesByDirection('HIN');
-        $this->assertCount(1, $outboundResult);
-        $this->assertSame($outboundPkw, $outboundResult[0]);
+        self::assertCount(1, $outboundResult);
+        self::assertSame($outboundPkw, $outboundResult[0]);
 
         $inboundResult = $travel->getTransportationServicesByDirection('RUECK');
-        $this->assertCount(1, $inboundResult);
-        $this->assertSame($inboundPkw, $inboundResult[0]);
+        self::assertCount(1, $inboundResult);
+        self::assertSame($inboundPkw, $inboundResult[0]);
     }
 
     /**
@@ -77,7 +77,7 @@ class TravelTest extends TestCase
         $result = $travel->getTransportationServicesByDirection('HIN');
 
         // Both PKW services should be returned (filtering happens at field options provider level)
-        $this->assertCount(2, $result);
+        self::assertCount(2, $result);
     }
 
     /**
@@ -104,9 +104,9 @@ class TravelTest extends TestCase
 
         $result = $travel->getTransportationServicesByDirection('HIN');
 
-        $this->assertCount(2, $result);
+        self::assertCount(2, $result);
         // BUS comes before PKW alphabetically
-        $this->assertSame('BUS', $result[0]->subType);
-        $this->assertSame('PKW', $result[1]->subType);
+        self::assertSame('BUS', $result[0]->subType);
+        self::assertSame('PKW', $result[1]->subType);
     }
 }