feature: Add optimistic offline lock (#1306) (#2551)

optimistic-offline-lock/src/test/java/com/iluwatar/OptimisticLockTest.java

@@ -0,0 +1,60 @@
+package com.iluwatar;
+
+import com.iluwatar.exception.ApplicationException;
+import com.iluwatar.model.Card;
+import com.iluwatar.repository.JpaRepository;
+import com.iluwatar.service.CardUpdateService;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.eq;
+
+@SuppressWarnings({"rawtypes", "unchecked"})
+public class OptimisticLockTest {
+
+  private CardUpdateService cardUpdateService;
+
+  private JpaRepository cardRepository;
+
+  @BeforeEach
+  public void setUp() {
+    cardRepository = Mockito.mock(JpaRepository.class);
+    cardUpdateService = new CardUpdateService(cardRepository);
+  }
+
+  @Test
+  public void shouldNotUpdateEntityOnDifferentVersion() {
+    int initialVersion = 1;
+    long cardId = 123L;
+    Card card = Card.builder()
+        .id(cardId)
+        .version(initialVersion)
+        .sum(123f)
+        .build();
+    when(cardRepository.findById(eq(cardId))).thenReturn(card);
+    when(cardRepository.getEntityVersionById(Mockito.eq(cardId))).thenReturn(initialVersion + 1);
+
+    Assertions.assertThrows(ApplicationException.class,
+        () -> cardUpdateService.doUpdate(card, cardId));
+  }
+
+  @Test
+  public void shouldUpdateOnSameVersion() {
+    int initialVersion = 1;
+    long cardId = 123L;
+    Card card = Card.builder()
+        .id(cardId)
+        .version(initialVersion)
+        .sum(123f)
+        .build();
+    when(cardRepository.findById(eq(cardId))).thenReturn(card);
+    when(cardRepository.getEntityVersionById(Mockito.eq(cardId))).thenReturn(initialVersion);
+
+    cardUpdateService.doUpdate(card, cardId);
+
+    Mockito.verify(cardRepository).update(Mockito.any());
+  }
+}