created test write offer with validproduct

src/test/java/de/rwu/easydrop/service/writer/OfferWriterTest.java

@@ -36,9 +36,6 @@ public class OfferWriterTest {
         offerWriter = new OfferWriter(persistence);
     }
 
-
-
-
     @Test
     void writeOfferToPersistence_InvalidProduct_ThrowsException() {
         //Arrange
@@ -50,6 +47,30 @@ public class OfferWriterTest {
         assertThrows(Exception.class, () -> offerWriter.writeOfferToPersistence(offer));
     }
 
+     @Test
+    void writeOfferToPresistence_ValidProduct_CallsSaveProduct(){
+
+        // Arrange
+        Product product = new Product();
+        product.setProductId("12345");
+        product.setDataOrigin(Webshop.AMAZON);
+        product.setCurrentPrice(9.99);
+        
+        // Arrange
+        Offer offer = new Offer();
+        offer.setOfferId("26876");
+        offer.setLastUpdate("2022-12-25");
+        offer.setSourceProduct(product);
+        offer.setTargetProduct(product);
+
+        // Act
+        offerWriter.writeOfferToPersistence(offer);
+
+        // Assert
+        Mockito.verify(persistence).writeOffer(any(OfferDTO.class));
+
+    }
+