test: coinflip service

backend/src/test/java/de/szut/casino/coinflip/CoinflipServiceTest.java

@@ -0,0 +1,64 @@
+package de.szut.casino.coinflip;
+
+import de.szut.casino.shared.service.BalanceService;
+import de.szut.casino.user.UserEntity;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.math.BigDecimal;
+import java.util.Random;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+class CoinflipServiceTest {
+
+    @Mock
+    private BalanceService balanceService;
+
+    @Mock
+    private Random random;
+
+    @InjectMocks
+    private CoinflipService coinflipService;
+
+    private UserEntity user;
+    private CoinflipDto coinflipDto;
+
+    @BeforeEach
+    void setUp() {
+        MockitoAnnotations.openMocks(this);
+        user = new UserEntity();
+        user.setBalance(BigDecimal.valueOf(100));
+        coinflipDto = new CoinflipDto(BigDecimal.valueOf(10), CoinSide.HEAD);
+    }
+
+    @Test
+    void testPlay_userWins() {
+        when(random.nextBoolean()).thenReturn(true);
+
+        CoinflipResult result = coinflipService.play(user, coinflipDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(20), result.getPayout());
+        assertEquals(CoinSide.HEAD, result.getCoinSide());
+        verify(balanceService, times(1)).subtractFunds(user, BigDecimal.valueOf(10));
+        verify(balanceService, times(1)).addFunds(user, BigDecimal.valueOf(20));
+    }
+
+    @Test
+    void testPlay_userLoses() {
+        when(random.nextBoolean()).thenReturn(false);
+
+        CoinflipResult result = coinflipService.play(user, coinflipDto);
+
+        assertFalse(result.isWin());
+        assertEquals(BigDecimal.ZERO, result.getPayout());
+        assertEquals(CoinSide.TAILS, result.getCoinSide());
+        verify(balanceService, times(1)).subtractFunds(user, BigDecimal.valueOf(10));
+        verify(balanceService, never()).addFunds(any(), any());
+    }
+}