Add integration tests for hateoas controller

Reproduce spring-projects/spring-hateoas#2160

rest/src/main/java/payroll/Employee.java

@@ -1,69 +1,67 @@
 package payroll;
 
-import java.util.Objects;
-
 import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.Id;
+import java.util.Objects;
 
 @Entity
-class Employee {
+public class Employee {
 
-	private @Id @GeneratedValue Long id;
-	private String name;
-	private String role;
+    private @Id @GeneratedValue Long id;
+    private String name;
+    private String role;
 
-	Employee() {}
+    public Employee() {}
 
-	Employee(String name, String role) {
+    Employee(String name, String role) {
 
-		this.name = name;
-		this.role = role;
-	}
+        this.name = name;
+        this.role = role;
+    }
 
-	public Long getId() {
-		return this.id;
-	}
+    public Long getId() {
+        return this.id;
+    }
 
-	public String getName() {
-		return this.name;
-	}
+    public String getName() {
+        return this.name;
+    }
 
-	public String getRole() {
-		return this.role;
-	}
+    public String getRole() {
+        return this.role;
+    }
 
-	public void setId(Long id) {
-		this.id = id;
-	}
+    public void setId(Long id) {
+        this.id = id;
+    }
 
-	public void setName(String name) {
-		this.name = name;
-	}
+    public void setName(String name) {
+        this.name = name;
+    }
 
-	public void setRole(String role) {
-		this.role = role;
-	}
+    public void setRole(String role) {
+        this.role = role;
+    }
 
-	@Override
-	public boolean equals(Object o) {
+    @Override
+    public boolean equals(Object o) {
 
-		if (this == o)
-			return true;
-		if (!(o instanceof Employee))
-			return false;
-		Employee employee = (Employee) o;
-		return Objects.equals(this.id, employee.id) && Objects.equals(this.name, employee.name)
-				&& Objects.equals(this.role, employee.role);
-	}
+        if (this == o) return true;
+        if (!(o instanceof Employee)) return false;
+        Employee employee = (Employee) o;
+        return Objects.equals(this.id, employee.id)
+                && Objects.equals(this.name, employee.name)
+                && Objects.equals(this.role, employee.role);
+    }
 
-	@Override
-	public int hashCode() {
-		return Objects.hash(this.id, this.name, this.role);
-	}
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.id, this.name, this.role);
+    }
 
-	@Override
-	public String toString() {
-		return "Employee{" + "id=" + this.id + ", name='" + this.name + '\'' + ", role='" + this.role + '\'' + '}';
-	}
+    @Override
+    public String toString() {
+        return "Employee{" + "id=" + this.id + ", name='" + this.name + '\'' + ", role='" + this.role + '\'' + '}';
+    }
 }

rest/src/test/java/EmployeeControllerIT.java

@@ -0,0 +1,78 @@
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.hateoas.CollectionModel;
+import org.springframework.hateoas.EntityModel;
+import org.springframework.hateoas.MediaTypes;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import payroll.Employee;
+import payroll.PayrollApplication;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+@SpringBootTest(classes = PayrollApplication.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+public class EmployeeControllerIT {
+
+    @Value(value = "${local.server.port}")
+    private int port;
+
+    private TestRestTemplate rest;
+
+    @BeforeEach
+    public void setup() {
+        rest = new TestRestTemplate(new RestTemplateBuilder().rootUri("http://localhost:" + port));
+    }
+
+    @Test
+    public void testGettingAllEmployeesWithAcceptHalFormsHeader() {
+        final var headers = new HttpHeaders();
+        headers.add("Accept", MediaTypes.HAL_FORMS_JSON_VALUE);
+        var httpEntity = new HttpEntity<>(headers);
+        var response = rest.exchange(
+                "/employees",
+                HttpMethod.GET,
+                httpEntity,
+                new ParameterizedTypeReference<CollectionModel<EntityModel<Employee>>>() {});
+        var resources = response.getBody();
+        assertThat(resources.getContent()).isNotNull();
+        var employees = resources.getContent();
+        System.out.println(resources);
+        assertThat(employees).isNotNull();
+        assertThat(employees.size()).isEqualTo(2);
+    }
+
+    @Test
+    public void testGettingAllEmployeesWithoutAcceptHalFormsHeader() {
+        var response = rest.exchange(
+                "/employees",
+                HttpMethod.GET,
+                new HttpEntity<>(null, null),
+                new ParameterizedTypeReference<CollectionModel<EntityModel<Employee>>>() {});
+        var resources = response.getBody();
+        assertThat(resources.getContent()).isNotNull();
+        var employees = resources.getContent();
+        // NB! resources returns empty content in collection model
+        System.out.println(resources);
+        assertThat(employees).isNotNull();
+        assertThat(employees.size()).isEqualTo(2);
+    }
+
+    @Test
+    public void testGettingAllEmployeesWithStringResponse() {
+        var response = rest.exchange(
+                "/employees",
+                HttpMethod.GET,
+                new HttpEntity<>(null, null),
+                String.class); // Deserialize to String to check that body is not empty
+        var resources = response.getBody();
+        assertThat(resources).isNotNull();
+        // NB! when deserializing to String, the response body is not empty
+        System.out.println(resources);
+    }
+}