added invalid offerexception test

src/test/java/de/rwu/easydrop/service/validation/OfferValidatorTest.java

@@ -1,9 +1,13 @@
 package de.rwu.easydrop.service.validation;
 
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
 
+import de.rwu.easydrop.exception.InvalidOfferException;
 import de.rwu.easydrop.model.Offer;
 
 
@@ -19,5 +23,13 @@ public class OfferValidatorTest {
         // Act and Assert
         assertDoesNotThrow(() -> OfferValidator.validate(offer));
     }
+
+    @ParameterizedTest
+    @MethodSource("invalidOffer")
+    void validate_InvalidOffer_ThrowsInvalidOfferException(Offer offer) {
+        // Act and Assert
+        assertThrows(InvalidOfferException.class, () -> OfferValidator.validate(offer));
+    }
+
     
 }