diff --git a/src/test/java/de/szut/lf8_starter/integration/project/AddEmployeeToProjectTest.java b/src/test/java/de/szut/lf8_starter/integration/project/AddEmployeeToProjectTest.java
index 4193e77..ab06823 100644
--- a/src/test/java/de/szut/lf8_starter/integration/project/AddEmployeeToProjectTest.java
+++ b/src/test/java/de/szut/lf8_starter/integration/project/AddEmployeeToProjectTest.java
@@ -45,17 +45,97 @@ class AddEmployeeToProjectActionIntegrationTest {
         project.setEmployees(List.of(1L, 2L, 3L));
         this.projectRepository.save(project);
 
-
-        mockMvc.perform(post("/projects/{projectId}/employees/{employeeId}", 1, 312)
+        mockMvc.perform(post("/projects/{projectId}/employees/{employeeId}", project.getId(), 312)
                         .header(HttpHeaders.AUTHORIZATION, getBearerToken())
                         .contentType(MediaType.APPLICATION_JSON))
                 .andExpect(status().isNoContent());
 
-        ProjectEntity updatedProject = projectRepository.findById(1L).get();
+        ProjectEntity updatedProject = projectRepository.findById(project.getId()).get();
 
         assert updatedProject.getEmployees().contains(312L);
     }
 
+    @Test
+    void addEmployeeToPastProjectTest() throws Exception {
+        ProjectEntity project = new ProjectEntity();
+        project.setComment("past project");
+        project.setContractor(1);
+        project.setContractorName("contractorName");
+        project.setEndDate(LocalDate.of(1991, 1, 1));
+        project.setLeadingEmployee(1);
+        project.setName("past project");
+        project.setStartDate(LocalDate.of(1990, 1, 1));
+        project.setEmployees(List.of(1L, 2L, 3L));
+        this.projectRepository.save(project);
+
+        mockMvc.perform(post("/projects/{projectId}/employees/{employeeId}", project.getId(), 312)
+                        .header(HttpHeaders.AUTHORIZATION, getBearerToken())
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().isNoContent());
+
+        ProjectEntity updatedProject = projectRepository.findById(project.getId()).get();
+
+        assert updatedProject.getEmployees().contains(312L);
+    }
+
+    @Test
+    void addEmployeeToFutureProjectTest() throws Exception {
+        ProjectEntity project = new ProjectEntity();
+        project.setComment("future project");
+        project.setContractor(1);
+        project.setContractorName("contractorName");
+        project.setEndDate(LocalDate.of(2101, 1, 1));
+        project.setLeadingEmployee(1);
+        project.setName("future project");
+        project.setStartDate(LocalDate.of(2100, 1, 1));
+        project.setEmployees(List.of(1L, 2L, 3L));
+        this.projectRepository.save(project);
+
+        mockMvc.perform(post("/projects/{projectId}/employees/{employeeId}", project.getId(), 312)
+                        .header(HttpHeaders.AUTHORIZATION, getBearerToken())
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().isNoContent());
+
+        ProjectEntity updatedProject = projectRepository.findById(project.getId()).get();
+
+        assert updatedProject.getEmployees().contains(312L);
+    }
+
+    @Test
+    void addEmployeeToProjectWithOverlappingDatesTest() throws Exception {
+        ProjectEntity project1 = new ProjectEntity();
+        project1.setComment("project 1");
+        project1.setContractor(1);
+        project1.setContractorName("contractorName");
+        project1.setEndDate(LocalDate.of(2023, 1, 1));
+        project1.setLeadingEmployee(1);
+        project1.setName("project 1");
+        project1.setStartDate(LocalDate.of(2022, 1, 1));
+        project1.setEmployees(List.of(1L, 2L, 3L));
+        this.projectRepository.save(project1);
+
+        ProjectEntity project2 = new ProjectEntity();
+        project2.setComment("project 2");
+        project2.setContractor(1);
+        project2.setContractorName("contractorName");
+        project2.setEndDate(LocalDate.of(2023, 6, 1));
+        project2.setLeadingEmployee(1);
+        project2.setName("project 2");
+        project2.setStartDate(LocalDate.of(2022, 6, 1));
+        project2.setEmployees(List.of(1L, 2L, 3L));
+        this.projectRepository.save(project2);
+
+        mockMvc.perform(post("/projects/{projectId}/employees/{employeeId}", project1.getId(), 312)
+                        .header(HttpHeaders.AUTHORIZATION, getBearerToken())
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().isNoContent());
+
+        mockMvc.perform(post("/projects/{projectId}/employees/{employeeId}", project2.getId(), 312)
+                        .header(HttpHeaders.AUTHORIZATION, getBearerToken())
+                        .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(status().isConflict());
+    }
+
     private String getBearerToken() {
         String url = "https://keycloak.szut.dev/auth/realms/szut/protocol/openid-connect/token";
 
@@ -74,4 +154,4 @@ class AddEmployeeToProjectActionIntegrationTest {
 
         return Objects.requireNonNull(response.getBody()).get("access_token").toString();
     }
-}
+}
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