Add unit tests for ResponseValidator with Mockito integration

Introduced `ResponseValidatorTest` to comprehensively test the `ResponseValidator` class. Enhanced the project dependencies by updating JUnit to 5.12.2 and integrating Mockito with `mockito-junit-jupiter` 5.17.0 for mocking support. Clarified Javadoc for handling `RecordMultipleResponse` cases in `ResponseValidator`.

src/test/java/codes/thischwa/cf/ResponseValidatorTest.java

@@ -0,0 +1,99 @@
+package codes.thischwa.cf;
+
+import codes.thischwa.cf.model.AbstractResponse;
+import codes.thischwa.cf.model.RecordMultipleResponse;
+import codes.thischwa.cf.model.ResponseResultInfo;
+import codes.thischwa.cf.model.ResultInfo;
+import java.util.Arrays;
+import lombok.Getter;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class ResponseValidatorTest {
+
+  @Mock
+  private AbstractResponse mockResponse;
+
+  @Mock
+  private ResponseResultInfo mockResultInfo;
+
+  @Mock
+  private RecordMultipleResponse mockMultipleResponse;
+
+  private ResponseValidator validatorWithException;
+  private ResponseValidator validatorWithoutException;
+
+  @BeforeEach
+  void setUp() {
+    validatorWithException = new ResponseValidator(true);
+    validatorWithoutException = new ResponseValidator(false);
+  }
+
+  @Test
+  void validateSuccessfulResponse() {
+    when(mockResponse.getResponseResultInfo()).thenReturn(mockResultInfo);
+    when(mockResultInfo.isSuccess()).thenReturn(true);
+
+    assertDoesNotThrow(() -> validatorWithException.validate(mockResponse, false));
+  }
+
+  @Test
+  void validateFailedResponse() {
+    when(mockResponse.getResponseResultInfo()).thenReturn(mockResultInfo);
+    when(mockResultInfo.isSuccess()).thenReturn(false);
+    when(mockResultInfo.getErrors()).thenReturn(Arrays.asList("Fehler 1", "Fehler 2"));
+
+    CloudflareApiException exception = assertThrows(CloudflareApiException.class,
+        () -> validatorWithException.validate(mockResponse, false));
+    assertTrue(exception.getMessage().contains("Fehler 1"));
+    assertTrue(exception.getMessage().contains("Fehler 2"));
+  }
+
+  @Test
+  void validateSingleResultExpectedButMultipleFound() {
+    when(mockMultipleResponse.getResponseResultInfo()).thenReturn(mockResultInfo);
+    when(mockResultInfo.isSuccess()).thenReturn(true);
+    when(mockMultipleResponse.getResultInfo()).thenReturn(new TestResultInfo(2));
+
+    CloudflareApiException exception = assertThrows(CloudflareApiException.class,
+        () -> validatorWithException.validate(mockMultipleResponse, true));
+    assertTrue(exception.getMessage().contains("Unexpected result count: 2"));
+  }
+
+  @Test
+  void validateEmptyResultWithExceptionEnabled() {
+    when(mockMultipleResponse.getResponseResultInfo()).thenReturn(mockResultInfo);
+    when(mockResultInfo.isSuccess()).thenReturn(true);
+    when(mockMultipleResponse.getResultInfo()).thenReturn(new TestResultInfo(0));
+
+    assertThrows(CloudflareNotFoundException.class,
+        () -> validatorWithException.validate(mockMultipleResponse, false));
+  }
+
+  @Test
+  void validateEmptyResultWithExceptionDisabled() {
+    when(mockMultipleResponse.getResponseResultInfo()).thenReturn(mockResultInfo);
+    when(mockResultInfo.isSuccess()).thenReturn(true);
+    when(mockMultipleResponse.getResultInfo()).thenReturn(new TestResultInfo(0));
+
+    assertDoesNotThrow(() -> validatorWithoutException.validate(mockMultipleResponse, true));
+  }
+
+  @Getter
+  private static class TestResultInfo extends ResultInfo {
+    private final int totalCount;
+
+    TestResultInfo(int totalCount) {
+      this.totalCount = totalCount;
+    }
+  }
+}