backend/src/main/java/de/szut/casino/blackjack/BlackJackGameEntity.java

@@ -4,8 +4,6 @@ import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonManagedReference;
 import de.szut.casino.user.UserEntity;
 import jakarta.persistence.*;
-import jakarta.validation.constraints.NotNull;
-import jakarta.validation.constraints.Positive;
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 import lombok.NoArgsConstructor;

backend/src/main/java/de/szut/casino/dice/DiceDto.java

@@ -5,12 +5,14 @@ import jakarta.validation.constraints.DecimalMax;
 import jakarta.validation.constraints.DecimalMin;
 import jakarta.validation.constraints.NotNull;
 import lombok.Getter;
+import lombok.NoArgsConstructor;
 import lombok.Setter;
 
 import java.math.BigDecimal;
 
 @Getter
 @Setter
+@NoArgsConstructor
 public class DiceDto extends BetDto {
     private boolean rollOver;
 

backend/src/main/java/de/szut/casino/dice/DiceService.java

@@ -11,10 +11,11 @@ import java.util.Random;
 @Service
 public class DiceService {
     private static final int MAX_DICE_VALUE = 100;
-    private final Random random = new Random();
+    private final Random random;
     private final BalanceService balanceService;
 
-    public DiceService(BalanceService balanceService) {
+    public DiceService(Random random, BalanceService balanceService) {
+        this.random = random;
         this.balanceService = balanceService;
     }
 

backend/src/test/java/de/szut/casino/dice/DiceServiceTest.java

@@ -0,0 +1,251 @@
+package de.szut.casino.dice;
+
+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.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.util.Random;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class DiceServiceTest {
+
+    @Mock
+    private BalanceService balanceService;
+
+    @Mock
+    private Random random;
+
+    @InjectMocks
+    private DiceService diceService;
+
+    private UserEntity user;
+    private DiceDto diceDto;
+
+    @BeforeEach
+    void setUp() {
+        user = new UserEntity();
+        user.setId(1L);
+        user.setBalance(BigDecimal.valueOf(1000));
+
+        diceDto = new DiceDto();
+        diceDto.setBetAmount(BigDecimal.valueOf(10));
+        diceDto.setTargetValue(BigDecimal.valueOf(50));
+        diceDto.setRollOver(true);
+    }
+
+    @Test
+    void play_rollOver_win() {
+        diceDto.setRollOver(true);
+        diceDto.setTargetValue(BigDecimal.valueOf(50));
+        when(random.nextInt(anyInt())).thenReturn(55);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(56), result.getRolledValue());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, times(1)).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollOver_lose() {
+        diceDto.setRollOver(true);
+        diceDto.setTargetValue(BigDecimal.valueOf(50));
+        when(random.nextInt(anyInt())).thenReturn(49);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertFalse(result.isWin());
+        assertEquals(BigDecimal.valueOf(50), result.getRolledValue());
+        assertEquals(BigDecimal.ZERO, result.getPayout());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, never()).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollUnder_win() {
+        diceDto.setRollOver(false);
+        diceDto.setTargetValue(BigDecimal.valueOf(50));
+        when(random.nextInt(anyInt())).thenReturn(48);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(49), result.getRolledValue());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, times(1)).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollUnder_lose() {
+        diceDto.setRollOver(false);
+        diceDto.setTargetValue(BigDecimal.valueOf(50));
+        when(random.nextInt(anyInt())).thenReturn(50);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertFalse(result.isWin());
+        assertEquals(BigDecimal.valueOf(51), result.getRolledValue());
+        assertEquals(BigDecimal.ZERO, result.getPayout());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, never()).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollOver_targetValueOne_rolledOne_lose() {
+        diceDto.setRollOver(true);
+        diceDto.setTargetValue(BigDecimal.valueOf(1));
+        when(random.nextInt(anyInt())).thenReturn(0);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertFalse(result.isWin());
+        assertEquals(BigDecimal.valueOf(1), result.getRolledValue());
+        assertEquals(BigDecimal.ZERO, result.getPayout());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, never()).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollOver_targetValueOne_rolledTwo_win() {
+        diceDto.setRollOver(true);
+        diceDto.setTargetValue(BigDecimal.valueOf(1));
+        when(random.nextInt(anyInt())).thenReturn(1);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(2), result.getRolledValue());
+        // Win chance for target 1 (roll over) is 99. Multiplier = (100-1)/99 = 1
+        assertEquals(diceDto.getBetAmount().stripTrailingZeros(), result.getPayout().stripTrailingZeros());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, times(1)).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollUnder_targetValueOne_alwaysLose_winChanceZero() {
+        diceDto.setRollOver(false);
+        diceDto.setTargetValue(BigDecimal.valueOf(1));
+        when(random.nextInt(anyInt())).thenReturn(0);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertFalse(result.isWin());
+        assertEquals(BigDecimal.valueOf(1), result.getRolledValue());
+        assertEquals(BigDecimal.ZERO, result.getPayout());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, never()).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollOver_targetValueNinetyNine_rolledHundred_win() {
+        diceDto.setRollOver(true);
+        diceDto.setTargetValue(BigDecimal.valueOf(99));
+        when(random.nextInt(anyInt())).thenReturn(99);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(100), result.getRolledValue());
+        // Win chance for target 99 (roll over) is 1. Multiplier = (100-1)/1 = 99
+        assertEquals(diceDto.getBetAmount().multiply(BigDecimal.valueOf(99)).stripTrailingZeros(), result.getPayout().stripTrailingZeros());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, times(1)).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollUnder_targetValueNinetyNine_rolledNinetyEight_win() {
+        diceDto.setRollOver(false);
+        diceDto.setTargetValue(BigDecimal.valueOf(99));
+        when(random.nextInt(anyInt())).thenReturn(97);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(98), result.getRolledValue());
+        // Win chance for target 99 (roll under) is 98. Multiplier = (100-1)/98 = 99/98
+        assertEquals(diceDto.getBetAmount().multiply(BigDecimal.valueOf(99).divide(BigDecimal.valueOf(98), 4, RoundingMode.HALF_UP)), result.getPayout());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, times(1)).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollOver_targetValueOneHundred_alwaysLose_winChanceZero() {
+        diceDto.setRollOver(true);
+        diceDto.setTargetValue(BigDecimal.valueOf(100));
+        when(random.nextInt(anyInt())).thenReturn(99);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertFalse(result.isWin());
+        assertEquals(BigDecimal.valueOf(100), result.getRolledValue());
+        assertEquals(BigDecimal.ZERO, result.getPayout());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, never()).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_rollUnder_targetValueOneHundred_rolledNinetyNine_win() {
+        diceDto.setRollOver(false);
+        diceDto.setTargetValue(BigDecimal.valueOf(100));
+        when(random.nextInt(anyInt())).thenReturn(98);
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(99), result.getRolledValue());
+        // Win chance for target 100 (roll under) is 99. Multiplier = (100-1)/99 = 1
+        assertEquals(diceDto.getBetAmount().stripTrailingZeros(), result.getPayout().stripTrailingZeros());
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+        verify(balanceService, times(1)).addFunds(eq(user), any(BigDecimal.class));
+    }
+
+    @Test
+    void play_payoutCalculationCorrect() {
+        diceDto.setRollOver(true);
+        diceDto.setTargetValue(BigDecimal.valueOf(75));
+        when(random.nextInt(anyInt())).thenReturn(75);
+
+        // Multiplier for win chance 25: (100-1)/25 = 99/25 = 3.96
+        // Payout: 10 * 3.96 = 39.6
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(39.6).stripTrailingZeros(), result.getPayout().stripTrailingZeros());
+    }
+
+    @Test
+    void play_payoutCalculationCorrect_rollUnder() {
+        diceDto.setRollOver(false);
+        diceDto.setTargetValue(BigDecimal.valueOf(25));
+        when(random.nextInt(anyInt())).thenReturn(0);
+
+        // Multiplier for win chance 24: (100-1)/24 = 99/24 = 4.125
+        // Payout: 10 * 4.125 = 41.25
+
+        DiceResult result = diceService.play(user, diceDto);
+
+        assertTrue(result.isWin());
+        assertEquals(BigDecimal.valueOf(41.25).stripTrailingZeros(), result.getPayout().stripTrailingZeros());
+    }
+
+    @Test
+    void play_betAmountSubtracted() {
+        when(random.nextInt(anyInt())).thenReturn(50);
+
+        diceService.play(user, diceDto);
+
+        verify(balanceService, times(1)).subtractFunds(user, diceDto.getBetAmount());
+    }
+}