diff --git a/src/test/java/de/rwth/swc/sqa/controller/CustomerTest.java b/src/test/java/de/rwth/swc/sqa/controller/CustomerTest.java
index 1500e7ba01841036d630a7135bc81b76c7f6154e..985f2af32dfa3426d4ebac5297623e01a1a40ebf 100644
--- a/src/test/java/de/rwth/swc/sqa/controller/CustomerTest.java
+++ b/src/test/java/de/rwth/swc/sqa/controller/CustomerTest.java
@@ -76,4 +76,30 @@ class CustomerTest {
                 .statusCode(expectedStatus);
     }
 
+    @Test
+    void customerInsertWithExistingId() {
+        // Create a new customer
+        Customer customer = new Customer();
+        customer.birthdate("2000-05-20");
+        customer.id(13L);
+
+        given().header("Content-Type", "application/json")
+                .body(customer)
+                .post(CUSTOMERS_PATH).then()
+                .assertThat()
+                .statusCode(201)
+                .body("birthdate", equalTo(customer.getBirthdate()))
+                .body("disabled", equalTo(false));
+
+        Customer customer2 = new Customer();
+        customer2.birthdate("2010-05-20");
+        customer2.id(13L);
+
+        given().header("Content-Type", "application/json")
+                .body(customer)
+                .post(CUSTOMERS_PATH).then()
+                .assertThat()
+                .statusCode(400);
+    }
+
 }
\ No newline at end of file
diff --git a/src/test/java/de/rwth/swc/sqa/controller/DiscountCardTest.java b/src/test/java/de/rwth/swc/sqa/controller/DiscountCardTest.java
index 84816a0d5f0da2d95a4c3a4bd438425512a8a775..50466f2b2b943af9281ae66e327264604814e04c 100644
--- a/src/test/java/de/rwth/swc/sqa/controller/DiscountCardTest.java
+++ b/src/test/java/de/rwth/swc/sqa/controller/DiscountCardTest.java
@@ -3,6 +3,10 @@ package de.rwth.swc.sqa.controller;
 import de.rwth.swc.sqa.model.Customer;
 import de.rwth.swc.sqa.model.DiscountCard;
 import io.restassured.RestAssured;
+import io.restassured.path.json.JsonPath;
+import io.restassured.response.Response;
+import org.json.JSONArray;
+import org.json.JSONObject;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -10,6 +14,9 @@ import org.junit.jupiter.params.provider.CsvSource;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.web.server.LocalServerPort;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import static io.restassured.RestAssured.given;
 import static org.hamcrest.Matchers.*;
 import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
diff --git a/src/test/java/de/rwth/swc/sqa/controller/TicketTest.java b/src/test/java/de/rwth/swc/sqa/controller/TicketTest.java
index 69f35a277ebd746360fa97332cae1659069264d3..e6ab96f8a4896fe2a5eec48cb951293338d6023f 100644
--- a/src/test/java/de/rwth/swc/sqa/controller/TicketTest.java
+++ b/src/test/java/de/rwth/swc/sqa/controller/TicketTest.java
@@ -2,6 +2,7 @@ package de.rwth.swc.sqa.controller;
 
 import de.rwth.swc.sqa.model.TicketRequest;
 import io.restassured.RestAssured;
+import io.swagger.models.auth.In;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -44,7 +45,6 @@ class TicketTest {
                 .body("validFrom", equalTo(ticket.getValidFrom()))
                 .body("validFor", equalTo(ticket.getValidFor().toString()))
                 .body("disabled", equalTo(false))
-                .body("discountCard", equalTo(0))
                 .body("student", equalTo(false))
                 .body("zone", equalTo(ticket.getZone().toString()));
     }
@@ -143,4 +143,25 @@ class TicketTest {
                 .statusCode(expectedStatus);
     }
 
+    @ParameterizedTest
+    @CsvSource({"25,201",
+            "50,201",
+            "33,400",
+            "100,400"})
+    void ticketWithInvalidDiscountCardValues(int givenValue, int expectedStatus) {
+        // Create a new ticket
+        TicketRequest ticket = new TicketRequest();
+        ticket.validFrom("2020-05-20T10:38:59");
+        ticket.birthdate("2000-05-20");
+        ticket.validFor(TicketRequest.ValidForEnum._1Y);
+        ticket.zone(TicketRequest.ZoneEnum.C);
+        ticket.discountCard(givenValue);
+
+        given().header("Content-Type", "application/json")
+                .body(ticket)
+                .post(TICKETS_PATH).then()
+                .assertThat()
+                .statusCode(expectedStatus);
+    }
+
 }
\ No newline at end of file