feat: Currency symbols enum

src/main/java/eu/ztsh/wymiana/config/CurrencyProperties.java

@@ -0,0 +1,9 @@
+package eu.ztsh.wymiana.config;
+
+import eu.ztsh.wymiana.model.Symbol;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties("currency")
+public record CurrencyProperties(Symbol initial) {
+
+}

src/main/java/eu/ztsh/wymiana/data/entity/CurrencyEntity.java

@@ -1,6 +1,9 @@
 package eu.ztsh.wymiana.data.entity;
 
+import eu.ztsh.wymiana.model.Symbol;
 import jakarta.persistence.Entity;
+import jakarta.persistence.EnumType;
+import jakarta.persistence.Enumerated;
 import jakarta.persistence.Id;
 import jakarta.persistence.Table;
 import lombok.AllArgsConstructor;
@@ -19,7 +22,8 @@ public class CurrencyEntity {
     @Id
     String pesel;
     @Id
-    String symbol;
+    @Enumerated(EnumType.STRING)
+    Symbol symbol;
     BigDecimal amount;
 
 }

src/main/java/eu/ztsh/wymiana/exception/NoDataException.java

@@ -1,8 +1,10 @@
 package eu.ztsh.wymiana.exception;
 
+import eu.ztsh.wymiana.model.Symbol;
+
 public class NoDataException extends RuntimeException {
 
-    public NoDataException(String code, String date) {
+    public NoDataException(Symbol code, String date) {
         super("No data for code %s and date %s".formatted(code, date));
     }
 

src/main/java/eu/ztsh/wymiana/model/Currency.java

@@ -2,6 +2,6 @@ package eu.ztsh.wymiana.model;
 
 import java.math.BigDecimal;
 
-public record Currency(String symbol, BigDecimal amount) {
+public record Currency(Symbol symbol, BigDecimal amount) {
 
 }

src/main/java/eu/ztsh/wymiana/model/Symbol.java

@@ -0,0 +1,6 @@
+package eu.ztsh.wymiana.model;
+
+public enum Symbol {
+    PLN,
+    USD
+}

src/main/java/eu/ztsh/wymiana/model/User.java

@@ -2,6 +2,6 @@ package eu.ztsh.wymiana.model;
 
 import java.util.Map;
 
-public record User(String name, String surname, String pesel, Map<String, Currency> currencies) {
+public record User(String name, String surname, String pesel, Map<Symbol, Currency> currencies) {
 
 }

src/main/java/eu/ztsh/wymiana/model/UserCreateRequestConfiguredWrapper.java

@@ -0,0 +1,65 @@
+package eu.ztsh.wymiana.model;
+
+import eu.ztsh.wymiana.web.model.UserCreateRequest;
+
+import java.math.BigDecimal;
+
+public class UserCreateRequestConfiguredWrapper {
+
+    private final UserCreateRequest request;
+    private final Symbol initialSymbol;
+
+    public String name() {
+        return request.name();
+    }
+
+    public String surname() {
+        return request.surname();
+    }
+
+    public String pesel() {
+        return request.pesel();
+    }
+
+    public BigDecimal initial() {
+        return request.initial();
+    }
+
+    public Symbol initialSymbol() {
+        return initialSymbol;
+    }
+
+    private UserCreateRequestConfiguredWrapper(Builder builder) {
+        this.request = builder.request;
+        this.initialSymbol = builder.initial;
+    }
+
+    public static Builder of(UserCreateRequest request) {
+        return new Builder().withRequest(request);
+    }
+
+    public static final class Builder {
+
+        private UserCreateRequest request;
+        private Symbol initial;
+
+        private Builder() {
+        }
+
+        private Builder withRequest(UserCreateRequest request) {
+            this.request = request;
+            return this;
+        }
+
+        public Builder withInitial(Symbol initial) {
+            this.initial = initial;
+            return this;
+        }
+
+        public UserCreateRequestConfiguredWrapper build() {
+            return new UserCreateRequestConfiguredWrapper(this);
+        }
+
+    }
+
+}

src/main/java/eu/ztsh/wymiana/service/CurrencyService.java

@@ -4,6 +4,7 @@ import eu.ztsh.wymiana.exception.ExchangeFailedException;
 import eu.ztsh.wymiana.exception.InsufficientFundsException;
 import eu.ztsh.wymiana.exception.UserNotFoundException;
 import eu.ztsh.wymiana.model.Currency;
+import eu.ztsh.wymiana.model.Symbol;
 import eu.ztsh.wymiana.model.User;
 import eu.ztsh.wymiana.validation.InstanceValidator;
 import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
@@ -28,23 +29,17 @@ public class CurrencyService {
     public User exchange(CurrencyExchangeRequest request) {
         validator.validate(request);
         return userService.get(request.pesel()).map(user -> {
-                if (!request.from().equalsIgnoreCase("PLN") && !request.to().equalsIgnoreCase("PLN")) {
+                if (!request.from().equals(Symbol.PLN) && !request.to().equals(Symbol.PLN)) {
                     throw new ExchangeFailedException("Either 'from' or 'to' has to be PLN");
                 }
-                // As we support only USD now, we need to limit second parameter too
-                // Begin: unlock other currencies
-                if (!request.from().equalsIgnoreCase("USD") && !request.to().equalsIgnoreCase("USD")) {
-                    throw new ExchangeFailedException("Either 'from' or 'to' has to be USD");
-                }
-                // End: unlock other currencies
 
-                var from = user.currencies().get(request.from().toUpperCase());
+                var from = user.currencies().get(request.from());
                 if (from == null) {
                     // There is no currency 'from' opened so no need to check if user has funds to exchange
                     throw new InsufficientFundsException();
                 }
                 var exchanged = performExchange(from,
-                    Optional.ofNullable(user.currencies().get(request.to().toUpperCase())).orElse(create(request.to())),
+                    Optional.ofNullable(user.currencies().get(request.to())).orElse(create(request.to())),
                     Optional.ofNullable(request.toSell()).orElse(BigDecimal.ZERO),
                     Optional.ofNullable(request.toBuy()).orElse(BigDecimal.ZERO));
                 user.currencies().putAll(exchanged);
@@ -53,16 +48,15 @@ public class CurrencyService {
             .orElseThrow(() -> new UserNotFoundException(request));
     }
 
-    private Currency create(String symbol) {
+    private Currency create(Symbol symbol) {
-        // TODO: check if supported - now limited to PLN <-> USD
+        return new Currency(symbol, BigDecimal.ZERO);
-        return new Currency(symbol.toUpperCase(), BigDecimal.ZERO);
     }
 
-    private Map<String, Currency> performExchange(Currency from, Currency to, BigDecimal toSell, BigDecimal toBuy) {
+    private Map<Symbol, Currency> performExchange(Currency from, Currency to, BigDecimal toSell, BigDecimal toBuy) {
         BigDecimal exchangeRate;
         BigDecimal neededFromAmount;
         BigDecimal requestedToAmount;
-        if (from.symbol().equalsIgnoreCase("PLN")) {
+        if (from.symbol().equals(Symbol.PLN)) {
             exchangeRate = nbpService.getSellRate(to.symbol());
             neededFromAmount = round(toBuy.signum() != 0 ? toBuy.multiply(exchangeRate) : toSell);
             requestedToAmount = round(toBuy.signum() != 0 ? toBuy : divide(toSell, exchangeRate));

src/main/java/eu/ztsh/wymiana/service/NbpService.java

@@ -2,6 +2,7 @@ package eu.ztsh.wymiana.service;
 
 import eu.ztsh.wymiana.exception.NoDataException;
 import eu.ztsh.wymiana.model.Rates;
+import eu.ztsh.wymiana.model.Symbol;
 import lombok.RequiredArgsConstructor;
 import org.assertj.core.util.VisibleForTesting;
 import org.springframework.http.HttpStatusCode;
@@ -29,17 +30,17 @@ public class NbpService {
     private static final String URI_PATTERN = "/api/exchangerates/rates/c/{code}/{date}/";
     private final DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd");
 
-    private final ConcurrentMap<String, RatesCache> cache = new ConcurrentHashMap<>(1);
+    private final ConcurrentMap<Symbol, RatesCache> cache = new ConcurrentHashMap<>(1);
 
-    public BigDecimal getSellRate(String currency) {
+    public BigDecimal getSellRate(Symbol currency) {
-        return getCurrency(currency.toUpperCase()).sell();
+        return getCurrency(currency).sell();
     }
 
-    public BigDecimal getBuyRate(String currency) {
+    public BigDecimal getBuyRate(Symbol currency) {
-        return getCurrency(currency.toUpperCase()).buy();
+        return getCurrency(currency).buy();
     }
 
-    private synchronized RatesCache getCurrency(String currency) {
+    private synchronized RatesCache getCurrency(Symbol currency) {
         var today = getFetchDate();
         var cacheObject = cache.get(currency);
         if (cacheObject == null || cacheObject.date().isBefore(today)) {
@@ -50,7 +51,7 @@ public class NbpService {
                 rate.getBid(),
                 rate.getAsk()
             );
-            cache.put(fresh.getCode(), cacheObject);
+            cache.put(Symbol.valueOf(fresh.getCode().toUpperCase()), cacheObject);
         }
         return cacheObject;
     }
@@ -69,8 +70,8 @@ public class NbpService {
     }
 
     @VisibleForTesting
-    Rates fetchData(String code, String date) {
+    Rates fetchData(Symbol code, String date) {
-        return restClient.get().uri(URI_PATTERN, code.toLowerCase(), date)
+        return restClient.get().uri(URI_PATTERN, code.name().toLowerCase(), date)
             .retrieve()
             .onStatus(HttpStatusCode::is4xxClientError, ((request, response) -> {
                 throw new NoDataException(code, date);

src/main/java/eu/ztsh/wymiana/service/UserService.java

@@ -1,8 +1,10 @@
 package eu.ztsh.wymiana.service;
 
+import eu.ztsh.wymiana.config.CurrencyProperties;
 import eu.ztsh.wymiana.data.repository.UserRepository;
 import eu.ztsh.wymiana.exception.UserAlreadyExistsException;
 import eu.ztsh.wymiana.model.User;
+import eu.ztsh.wymiana.model.UserCreateRequestConfiguredWrapper;
 import eu.ztsh.wymiana.util.UserMapper;
 import eu.ztsh.wymiana.validation.InstanceValidator;
 import eu.ztsh.wymiana.web.model.UserCreateRequest;
@@ -20,13 +22,16 @@ public class UserService {
 
     private final UserRepository userRepository;
     private final InstanceValidator validator;
+    private final CurrencyProperties currencyProperties;
 
     public User create(UserCreateRequest request) {
         validator.validate(request);
         if (userRepository.findById(request.pesel()).isPresent()) {
             throw new UserAlreadyExistsException(request);
         }
-        return UserMapper.entityToPojo(userRepository.save(UserMapper.requestToEntity(request)));
+        return UserMapper.entityToPojo(userRepository.save(UserMapper.requestToEntity(
+            UserCreateRequestConfiguredWrapper.of(request).withInitial(currencyProperties.initial()).build()
+        )));
     }
 
     public Optional<User> get(@PESEL String pesel) {

src/main/java/eu/ztsh/wymiana/util/CurrencyMapper.java

@@ -2,6 +2,7 @@ package eu.ztsh.wymiana.util;
 
 import eu.ztsh.wymiana.data.entity.CurrencyEntity;
 import eu.ztsh.wymiana.model.Currency;
+import eu.ztsh.wymiana.model.Symbol;
 
 import java.util.List;
 import java.util.Map;
@@ -17,12 +18,12 @@ public class CurrencyMapper {
         return new CurrencyEntity(pesel, pojo.symbol(), pojo.amount());
     }
 
-    public static Map<String, Currency> entitiesToPojoMap(List<CurrencyEntity> values) {
+    public static Map<Symbol, Currency> entitiesToPojoMap(List<CurrencyEntity> values) {
         return values.stream().map(CurrencyMapper::entityToPojo)
             .collect(Collectors.toMap(Currency::symbol, pojo -> pojo));
     }
 
-    public static List<CurrencyEntity> pojoMapToEntities(Map<String, Currency> currencies, String pesel) {
+    public static List<CurrencyEntity> pojoMapToEntities(Map<Symbol, Currency> currencies, String pesel) {
         return currencies.values().stream().map(entry -> pojoToEntity(entry, pesel)).toList();
     }
 

src/main/java/eu/ztsh/wymiana/util/UserMapper.java

@@ -3,7 +3,7 @@ package eu.ztsh.wymiana.util;
 import eu.ztsh.wymiana.data.entity.CurrencyEntity;
 import eu.ztsh.wymiana.data.entity.UserEntity;
 import eu.ztsh.wymiana.model.User;
-import eu.ztsh.wymiana.web.model.UserCreateRequest;
+import eu.ztsh.wymiana.model.UserCreateRequestConfiguredWrapper;
 
 import java.util.List;
 
@@ -19,9 +19,9 @@ public class UserMapper {
             CurrencyMapper.pojoMapToEntities(pojo.currencies(), pojo.pesel()));
     }
 
-    public static UserEntity requestToEntity(UserCreateRequest request) {
+    public static UserEntity requestToEntity(UserCreateRequestConfiguredWrapper request) {
         return new UserEntity(request.pesel(), request.name(), request.surname(),
-            List.of(new CurrencyEntity(request.pesel(), "PLN", request.initial())));
+            List.of(new CurrencyEntity(request.pesel(), request.initialSymbol(), request.initial())));
     }
 
     private UserMapper() {

src/main/java/eu/ztsh/wymiana/web/model/CurrencyExchangeRequest.java

@@ -1,5 +1,6 @@
 package eu.ztsh.wymiana.web.model;
 
+import eu.ztsh.wymiana.model.Symbol;
 import eu.ztsh.wymiana.validation.ValidExchangeRequest;
 import jakarta.validation.constraints.NotNull;
 import lombok.Builder;
@@ -11,8 +12,8 @@ import java.math.BigDecimal;
 @ValidExchangeRequest
 public record CurrencyExchangeRequest(
     @PESEL String pesel,
-    @NotNull String from,
+    @NotNull Symbol from,
-    @NotNull String to,
+    @NotNull Symbol to,
     BigDecimal toBuy,
     BigDecimal toSell
 ) {

src/main/resources/application.yaml

@@ -4,6 +4,8 @@ hsqldb:
 
 nbp:
   baseurl: "http://api.nbp.pl"
+currency:
+  initial: PLN
 
 spring:
   datasource:
@@ -14,6 +16,9 @@ spring:
   jpa:
     hibernate:
       ddl-auto: create
+  jackson:
+    mapper:
+      ACCEPT_CASE_INSENSITIVE_ENUMS: true
 
 management:
   endpoints:

src/test/java/eu/ztsh/wymiana/EntityCreator.java

@@ -5,6 +5,7 @@ import eu.ztsh.wymiana.data.entity.UserEntity;
 import eu.ztsh.wymiana.model.Currency;
 import eu.ztsh.wymiana.model.Rate;
 import eu.ztsh.wymiana.model.Rates;
+import eu.ztsh.wymiana.model.Symbol;
 import eu.ztsh.wymiana.model.User;
 import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
 import eu.ztsh.wymiana.web.model.UserCreateRequest;
@@ -29,8 +30,6 @@ public class EntityCreator {
         public static BigDecimal PLN = createScaled(20.10, 2);
         public static BigDecimal USD_SELL = createScaled(5.18, 2);
         public static BigDecimal USD_BUY = createScaled(5.08, 2);
-        public static String PLN_SYMBOL = "PLN";
-        public static String USD_SYMBOL = "USD";
         public static BigDecimal BUY_RATE = createScaled(3.8804, 4);
         public static BigDecimal SELL_RATE = createScaled(3.9572, 4);
 
@@ -45,12 +44,12 @@ public class EntityCreator {
     }
 
     public static User user(BigDecimal pln, BigDecimal usd) {
-        Map<String, Currency> currencies = new HashMap<>();
+        Map<Symbol, Currency> currencies = new HashMap<>();
         if (pln.signum() > 0) {
-            currencies.put("PLN", new Currency("PLN", pln));
+            currencies.put(Symbol.PLN, new Currency(Symbol.PLN, pln));
         }
         if (usd.signum() > 0) {
-            currencies.put("USD", new Currency("USD", usd));
+            currencies.put(Symbol.USD, new Currency(Symbol.USD, usd));
         }
         return new User(Constants.NAME, Constants.SURNAME, Constants.PESEL, currencies);
     }
@@ -74,7 +73,7 @@ public class EntityCreator {
         var rates = new Rates();
         rates.setTable("C");
         rates.setCurrency("dolar amerykański");
-        rates.setCode("USD");
+        rates.setCode(Symbol.USD.toString());
         var rate = new Rate();
         rate.setNo("096/C/NBP/2024");
         rate.setEffectiveDate(date);
@@ -129,13 +128,13 @@ public class EntityCreator {
             var nonnulPesel = Optional.ofNullable(pesel).orElse(Constants.PESEL);
             List<CurrencyEntity> currencies = new ArrayList<>();
             if (pln.signum() > -1) {
-                currencies.add(new CurrencyEntity(nonnulPesel, "PLN", pln));
+                currencies.add(new CurrencyEntity(nonnulPesel, Symbol.PLN, pln));
             }
             if (usd.signum() > -1) {
-                currencies.add(new CurrencyEntity(nonnulPesel, "USD", usd));
+                currencies.add(new CurrencyEntity(nonnulPesel, Symbol.USD, usd));
             }
             if (currencies.isEmpty()) {
-                currencies.add(new CurrencyEntity(nonnulPesel, "PLN", Constants.PLN));
+                currencies.add(new CurrencyEntity(nonnulPesel, Symbol.PLN, Constants.PLN));
             }
             return new UserEntity(
                 nonnulPesel,

src/test/java/eu/ztsh/wymiana/RepositoryBasedTest.java

@@ -29,6 +29,7 @@ public abstract class RepositoryBasedTest {
             .isNotEmpty()
             .get()
             .usingRecursiveComparison()
+            .ignoringCollectionOrder()
             .isEqualTo(entity);
     }
 

src/test/java/eu/ztsh/wymiana/service/CurrencyServiceTest.java

@@ -2,10 +2,11 @@ package eu.ztsh.wymiana.service;
 
 import eu.ztsh.wymiana.EntityCreator;
 import eu.ztsh.wymiana.RepositoryBasedTest;
+import eu.ztsh.wymiana.config.CurrencyProperties;
 import eu.ztsh.wymiana.data.repository.UserRepository;
-import eu.ztsh.wymiana.exception.ExchangeFailedException;
 import eu.ztsh.wymiana.exception.InsufficientFundsException;
 import eu.ztsh.wymiana.exception.UserNotFoundException;
+import eu.ztsh.wymiana.model.Symbol;
 import eu.ztsh.wymiana.validation.InstanceValidator;
 import eu.ztsh.wymiana.validation.ValidationFailedException;
 import jakarta.transaction.Transactional;
@@ -29,12 +30,14 @@ class CurrencyServiceTest extends RepositoryBasedTest {
     private final CurrencyService currencyService;
 
     @Autowired
-    public CurrencyServiceTest(UserRepository userRepository, InstanceValidator instanceValidator) {
+    public CurrencyServiceTest(UserRepository userRepository, InstanceValidator instanceValidator,
+                               CurrencyProperties currencyProperties) {
         super(userRepository);
         var nbp = Mockito.mock(NbpService.class);
-        Mockito.when(nbp.getSellRate("USD")).thenReturn(SELL_RATE);
+        Mockito.when(nbp.getSellRate(Symbol.USD)).thenReturn(SELL_RATE);
-        Mockito.when(nbp.getBuyRate("USD")).thenReturn(BUY_RATE);
+        Mockito.when(nbp.getBuyRate(Symbol.USD)).thenReturn(BUY_RATE);
-        currencyService = new CurrencyService(new UserService(userRepository, instanceValidator), nbp, instanceValidator);
+        currencyService = new CurrencyService(new UserService(userRepository, instanceValidator, currencyProperties),
+            nbp, instanceValidator);
     }
 
     @Transactional
@@ -43,12 +46,12 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var entity = EntityCreator.userEntity().build();
         userRepository.save(entity);
         var result = currencyService.exchange(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toSell(PLN)
             .build());
         assertThat(result.currencies())
-            .matches(map -> map.get(PLN_SYMBOL).amount().signum() == 0 && Objects.equals(map.get(USD_SYMBOL).amount(), USD_BUY), "USD 5.08");
+            .matches(map -> map.get(Symbol.PLN).amount().signum() == 0 && Objects.equals(map.get(Symbol.USD).amount(), USD_BUY), "USD 5.08");
         var expected = EntityCreator.userEntity().pln(0).usd(USD_BUY).build();
         expect(expected);
     }
@@ -59,12 +62,12 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var entity = EntityCreator.userEntity().build();
         userRepository.save(entity);
         var result = currencyService.exchange(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toBuy(USD_BUY)
             .build());
         assertThat(result.currencies())
-            .matches(map -> map.get(PLN_SYMBOL).amount().signum() == 0 && Objects.equals(map.get(USD_SYMBOL).amount(), USD_BUY));
+            .matches(map -> map.get(Symbol.PLN).amount().signum() == 0 && Objects.equals(map.get(Symbol.USD).amount(), USD_BUY));
         var expected = EntityCreator.userEntity().pln(0).usd(USD_BUY).build();
         expect(expected);
     }
@@ -75,12 +78,12 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var entity = EntityCreator.userEntity().pln(-1).usd(USD_SELL).build();
         userRepository.save(entity);
         var result = currencyService.exchange(EntityCreator.exchangeRequest()
-            .from(USD_SYMBOL)
+            .from(Symbol.USD)
-            .to(PLN_SYMBOL)
+            .to(Symbol.PLN)
             .toSell(USD_SELL)
             .build());
         assertThat(result.currencies())
-            .matches(map -> Objects.equals(map.get(PLN_SYMBOL).amount(), PLN) && map.get(USD_SYMBOL).amount().signum() == 0, "PLN 20.10");
+            .matches(map -> Objects.equals(map.get(Symbol.PLN).amount(), PLN) && map.get(Symbol.USD).amount().signum() == 0, "PLN 20.10");
         var expected = EntityCreator.userEntity().pln(PLN).usd(0).build();
         expect(expected);
     }
@@ -91,12 +94,12 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var entity = EntityCreator.userEntity().pln(-1).usd(USD_SELL).build();
         userRepository.save(entity);
         var result = currencyService.exchange(EntityCreator.exchangeRequest()
-            .from(USD_SYMBOL)
+            .from(Symbol.USD)
-            .to(PLN_SYMBOL)
+            .to(Symbol.PLN)
             .toBuy(PLN)
             .build());
         assertThat(result.currencies())
-            .matches(map -> Objects.equals(map.get(PLN_SYMBOL).amount(), PLN) && map.get(USD_SYMBOL).amount().signum() == 0, "PLN 20.10");
+            .matches(map -> Objects.equals(map.get(Symbol.PLN).amount(), PLN) && map.get(Symbol.USD).amount().signum() == 0, "PLN 20.10");
         var expected = EntityCreator.userEntity().pln(PLN).usd(0).build();
         expect(expected);
     }
@@ -107,8 +110,8 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var entity = EntityCreator.userEntity().build();
         userRepository.save(entity);
         var request = EntityCreator.exchangeRequest()
-            .from(USD_SYMBOL)
+            .from(Symbol.USD)
-            .to(PLN_SYMBOL)
+            .to(Symbol.PLN)
             .toBuy(PLN)
             .build();
         assertThatThrownBy(() -> currencyService.exchange(request))
@@ -121,14 +124,14 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var initialValue = BigDecimal.valueOf(100);
         var entity = EntityCreator.userEntity().pln(initialValue).build();
         userRepository.save(entity);
-        var result1 = currencyService.exchange(EntityCreator.exchangeRequest()
+        currencyService.exchange(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toBuy(USD_BUY)
             .build());
-        var result2 = currencyService.exchange(EntityCreator.exchangeRequest()
+        currencyService.exchange(EntityCreator.exchangeRequest()
-            .from(USD_SYMBOL)
+            .from(Symbol.USD)
-            .to(PLN_SYMBOL)
+            .to(Symbol.PLN)
             .toSell(USD_BUY)
             .build());
         var resultOptional = userRepository.findById(entity.getPesel());
@@ -137,7 +140,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var resultEntity = resultOptional.get();
         assertThat(resultEntity.getCurrencies()
             .stream()
-            .filter(c -> c.getSymbol().equalsIgnoreCase("PLN"))
+            .filter(c -> c.getSymbol().equals(Symbol.PLN))
             .findFirst()).isNotEmpty().get().matches(currencyEntity -> currencyEntity.getAmount().compareTo(initialValue) < 0);
     }
 
@@ -147,8 +150,8 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         var entity = EntityCreator.userEntity().build();
         userRepository.save(entity);
         var request = EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toBuy(PLN)
             .build();
         assertThatThrownBy(() -> currencyService.exchange(request))
@@ -161,8 +164,8 @@ class CurrencyServiceTest extends RepositoryBasedTest {
     void invalidPeselTest(String pesel) {
         var entity = EntityCreator.exchangeRequest()
             .pesel(pesel)
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toSell(USD_SELL)
             .build();
         assertThatThrownBy(() -> currencyService.exchange(entity))
@@ -173,8 +176,8 @@ class CurrencyServiceTest extends RepositoryBasedTest {
     @Test
     void notExistingUserTest() {
         var entity = EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toSell(USD_SELL)
             .build();
         assertThatThrownBy(() -> currencyService.exchange(entity))
@@ -185,7 +188,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
     @DisplayName("Empty 'from' value")
     void emptyFromTest() {
         var entity = EntityCreator.exchangeRequest()
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toSell(USD_SELL)
             .build();
         assertThatThrownBy(() -> currencyService.exchange(entity))
@@ -197,7 +200,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
     @DisplayName("Empty 'to' value")
     void emptyToTest() {
         var entity = EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
             .toSell(USD_SELL)
             .build();
         assertThatThrownBy(() -> currencyService.exchange(entity))

src/test/java/eu/ztsh/wymiana/service/NbpServiceTest.java

@@ -5,6 +5,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import eu.ztsh.wymiana.EntityCreator;
 import eu.ztsh.wymiana.WireMockExtension;
 import eu.ztsh.wymiana.exception.NoDataException;
+import eu.ztsh.wymiana.model.Symbol;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
@@ -79,7 +80,7 @@ class NbpServiceTest {
         var url = "/api/exchangerates/rates/c/usd/%s/".formatted(date);
         WireMockExtension.response(url, 200, new ObjectMapper().writeValueAsString(EntityCreator.rates(date)));
         try {
-            assertThat(nbpService.getSellRate(EntityCreator.Constants.USD_SYMBOL)).isEqualTo(EntityCreator.Constants.SELL_RATE);
+            assertThat(nbpService.getSellRate(Symbol.USD)).isEqualTo(EntityCreator.Constants.SELL_RATE);
         } finally {
             WireMockExtension.verifyGet(1, url);
         }
@@ -92,9 +93,9 @@ class NbpServiceTest {
         var url = "/api/exchangerates/rates/c/usd/%s/".formatted(date);
         WireMockExtension.response(url, 200, new ObjectMapper().writeValueAsString(EntityCreator.rates(date)));
         // save to cache
-        assertThat(nbpService.getSellRate(EntityCreator.Constants.USD_SYMBOL)).isEqualTo(EntityCreator.Constants.SELL_RATE);
+        assertThat(nbpService.getSellRate(Symbol.USD)).isEqualTo(EntityCreator.Constants.SELL_RATE);
         // get from cache
-        assertThat(nbpService.getBuyRate(EntityCreator.Constants.USD_SYMBOL)).isEqualTo(EntityCreator.Constants.BUY_RATE);
+        assertThat(nbpService.getBuyRate(Symbol.USD)).isEqualTo(EntityCreator.Constants.BUY_RATE);
         WireMockExtension.verifyGet(1, url);
     }
 
@@ -102,9 +103,9 @@ class NbpServiceTest {
     @Test
     void getInvalidCurrencyTest() {
         var date = dtf.format(updateClock(DayOfWeek.FRIDAY));
-        var url = "/api/exchangerates/rates/c/usb/%s/".formatted(date);
+        var url = "/api/exchangerates/rates/c/usd/%s/".formatted(date);
         WireMockExtension.response(url, 404, "404 NotFound - Not Found - Brak danych");
-        assertThatThrownBy(() -> nbpService.getSellRate("usb")).isInstanceOf(NoDataException.class);
+        assertThatThrownBy(() -> nbpService.getSellRate(Symbol.USD)).isInstanceOf(NoDataException.class);
         WireMockExtension.verifyGet(1, url);
     }
 

src/test/java/eu/ztsh/wymiana/service/UserServiceTest.java

@@ -2,6 +2,7 @@ package eu.ztsh.wymiana.service;
 
 import eu.ztsh.wymiana.EntityCreator;
 import eu.ztsh.wymiana.RepositoryBasedTest;
+import eu.ztsh.wymiana.config.CurrencyProperties;
 import eu.ztsh.wymiana.data.repository.UserRepository;
 import eu.ztsh.wymiana.exception.UserAlreadyExistsException;
 import eu.ztsh.wymiana.util.UserMapper;
@@ -21,9 +22,10 @@ class UserServiceTest extends RepositoryBasedTest {
     private final UserService userService;
 
     @Autowired
-    public UserServiceTest(UserRepository userRepository, InstanceValidator instanceValidator) {
+    public UserServiceTest(UserRepository userRepository, InstanceValidator instanceValidator,
+                           CurrencyProperties currencyProperties) {
         super(userRepository);
-        userService = new UserService(userRepository, instanceValidator);
+        userService = new UserService(userRepository, instanceValidator, currencyProperties);
     }
 
     @Test
@@ -42,8 +44,8 @@ class UserServiceTest extends RepositoryBasedTest {
         var second = EntityCreator.userRequest().build();
         userService.create(first);
         assertThatThrownBy(() -> userService.create(second))
-                .isInstanceOf(UserAlreadyExistsException.class)
+            .isInstanceOf(UserAlreadyExistsException.class)
-                .hasMessage("User with PESEL %s already exists".formatted(EntityCreator.Constants.PESEL));
+            .hasMessage("User with PESEL %s already exists".formatted(EntityCreator.Constants.PESEL));
     }
 
     @Test
@@ -51,13 +53,13 @@ class UserServiceTest extends RepositoryBasedTest {
     void createDuplicatedPeselTest() {
         var first = EntityCreator.userRequest().build();
         var second = EntityCreator.userRequest(30.30)
-                .name("Jan")
+            .name("Jan")
-                .surname("Kowalski")
+            .surname("Kowalski")
-                .build();
+            .build();
         userService.create(first);
         assertThatThrownBy(() -> userService.create(second))
-                .isInstanceOf(UserAlreadyExistsException.class)
+            .isInstanceOf(UserAlreadyExistsException.class)
-                .hasMessage("User with PESEL %s already exists".formatted(EntityCreator.Constants.PESEL));
+            .hasMessage("User with PESEL %s already exists".formatted(EntityCreator.Constants.PESEL));
     }
 
     @Test
@@ -65,8 +67,8 @@ class UserServiceTest extends RepositoryBasedTest {
     void youngUserTest() {
         var request = EntityCreator.userRequest().pesel("").build();
         assertThatThrownBy(() -> userService.create(request))
-                .isInstanceOf(ValidationFailedException.class)
+            .isInstanceOf(ValidationFailedException.class)
-                .hasMessageContaining(Adult.MESSAGE);
+            .hasMessageContaining(Adult.MESSAGE);
     }
 
     @Test
@@ -78,10 +80,10 @@ class UserServiceTest extends RepositoryBasedTest {
         var userOptional = userService.get(EntityCreator.Constants.PESEL);
         var expected = UserMapper.entityToPojo(entity);
         assertThat(userOptional)
-                .isNotEmpty()
+            .isNotEmpty()
-                .get()
+            .get()
-                .usingRecursiveComparison()
+            .usingRecursiveComparison()
-                .isEqualTo(expected);
+            .isEqualTo(expected);
     }
 
     @Test

src/test/java/eu/ztsh/wymiana/util/UserMapperTest.java

@@ -1,12 +1,10 @@
 package eu.ztsh.wymiana.util;
 
 import eu.ztsh.wymiana.EntityCreator;
-import eu.ztsh.wymiana.model.Currency;
+import eu.ztsh.wymiana.model.Symbol;
-import eu.ztsh.wymiana.model.User;
+import eu.ztsh.wymiana.model.UserCreateRequestConfiguredWrapper;
 import org.junit.jupiter.api.Test;
 
-import java.util.Map;
-
 import static org.assertj.core.api.Assertions.assertThat;
 
 class UserMapperTest {
@@ -31,7 +29,9 @@ class UserMapperTest {
 
     @Test
     void requestToEntityTest() {
-        var request = EntityCreator.userRequest().build();
+        var request = UserCreateRequestConfiguredWrapper.of(EntityCreator.userRequest().build())
+            .withInitial(Symbol.PLN)
+            .build() ;
         var expected = EntityCreator.userEntity().build();
         assertThat(UserMapper.requestToEntity(request))
             .usingRecursiveComparison()

src/test/java/eu/ztsh/wymiana/validation/ValidExchangeRequestValidatorTest.java

@@ -1,16 +1,15 @@
 package eu.ztsh.wymiana.validation;
 
 import eu.ztsh.wymiana.EntityCreator;
+import eu.ztsh.wymiana.model.Symbol;
 import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 import java.math.BigDecimal;
 
-import static eu.ztsh.wymiana.EntityCreator.Constants.PLN_SYMBOL;
 import static eu.ztsh.wymiana.EntityCreator.Constants.USD_BUY;
 import static eu.ztsh.wymiana.EntityCreator.Constants.USD_SELL;
-import static eu.ztsh.wymiana.EntityCreator.Constants.USD_SYMBOL;
 
 class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeRequestValidator, CurrencyExchangeRequest> {
 
@@ -22,8 +21,8 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
     @DisplayName("Valid request with buy value specified")
     void validRequestWithBuyTest() {
         assertThatValidation(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toBuy(USD_BUY)
             .build()).isTrue();
     }
@@ -32,8 +31,8 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
     @DisplayName("Valid request with sell value specified")
     void validRequestWithSellTest() {
         assertThatValidation(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toSell(USD_SELL)
             .build()).isTrue();
     }
@@ -42,8 +41,8 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
     @DisplayName("From and To have same value")
     void sameFromToTest() {
         assertThatValidation(EntityCreator.exchangeRequest()
-            .from(USD_SYMBOL)
+            .from(Symbol.USD)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toSell(USD_SELL)
             .build()).isFalse();
     }
@@ -52,8 +51,8 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
     @DisplayName("Empty amounts")
     void emptyBuySellTest() {
         assertThatValidation(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .build()).isFalse();
     }
 
@@ -61,8 +60,8 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
     @DisplayName("Both Buy and Sell params filled in")
     void bothFilledBuySellTest() {
         assertThatValidation(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toBuy(USD_BUY)
             .toSell(USD_SELL)
             .build()).isFalse();
@@ -72,8 +71,8 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
     @DisplayName("Negative buy amount value")
     void negativeBuyAmountTest() {
         assertThatValidation(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toBuy(BigDecimal.valueOf(-1.0))
             .build()).isFalse();
     }
@@ -82,8 +81,8 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
     @DisplayName("Negative sell amount value")
     void negativeSellAmountTest() {
         assertThatValidation(EntityCreator.exchangeRequest()
-            .from(PLN_SYMBOL)
+            .from(Symbol.PLN)
-            .to(USD_SYMBOL)
+            .to(Symbol.USD)
             .toSell(BigDecimal.valueOf(-1.0))
             .build()).isFalse();
     }

src/test/java/eu/ztsh/wymiana/web/ApplicationIntegrationTests.java

@@ -4,6 +4,7 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import eu.ztsh.wymiana.EntityCreator;
 import eu.ztsh.wymiana.WireMockExtension;
+import eu.ztsh.wymiana.model.Symbol;
 import eu.ztsh.wymiana.util.UserMapper;
 import org.junit.jupiter.api.ClassOrderer;
 import org.junit.jupiter.api.DisplayName;
@@ -153,8 +154,8 @@ class ApplicationIntegrationTests {
             webTestClient.post()
                 .uri(endpoint)
                 .bodyValue(EntityCreator.exchangeRequest()
-                    .from(PLN_SYMBOL)
+                    .from(Symbol.PLN)
-                    .to(USD_SYMBOL)
+                    .to(Symbol.USD)
                     .toSell(PLN)
                     .build())
                 .exchange()
@@ -174,8 +175,8 @@ class ApplicationIntegrationTests {
             webTestClient.post()
                 .uri(endpoint)
                 .bodyValue(EntityCreator.exchangeRequest()
-                    .from(PLN_SYMBOL)
+                    .from(Symbol.PLN)
-                    .to(USD_SYMBOL)
+                    .to(Symbol.USD)
                     .toSell(PLN)
                     .build())
                 .exchange()
@@ -191,8 +192,8 @@ class ApplicationIntegrationTests {
                 .uri(endpoint)
                 .bodyValue(EntityCreator.exchangeRequest()
                     .pesel(ANOTHER_PESEL)
-                    .from(PLN_SYMBOL)
+                    .from(Symbol.PLN)
-                    .to(USD_SYMBOL)
+                    .to(Symbol.USD)
                     .toSell(PLN)
                     .build())
                 .exchange()
@@ -207,8 +208,8 @@ class ApplicationIntegrationTests {
                 .uri(endpoint)
                 .bodyValue(EntityCreator.exchangeRequest()
                     .pesel(INVALID_PESEL)
-                    .from(PLN_SYMBOL)
+                    .from(Symbol.PLN)
-                    .to(USD_SYMBOL)
+                    .to(Symbol.USD)
                     .toSell(PLN)
                     .build())
                 .exchange()
@@ -221,14 +222,34 @@ class ApplicationIntegrationTests {
             webTestClient.post()
                 .uri(endpoint)
                 .bodyValue(EntityCreator.exchangeRequest()
-                    .from(USD_SYMBOL)
+                    .from(Symbol.USD)
-                    .to(PLN_SYMBOL)
+                    .to(Symbol.PLN)
                     .toBuy(PLN)
                     .build())
                 .exchange()
                 .expectStatus().isBadRequest();
         }
 
+        @Test
+        @DisplayName("03.6: Perform valid money exchange with lower case currency symbols")
+        void ignoreCaseTest() {
+            var date = getTodayOrLastFriday();
+            var expected = asJson(EntityCreator.user(BigDecimal.valueOf(100).subtract(PLN.multiply(BigDecimal.TWO)), USD_BUY.multiply(BigDecimal.TWO)));
+            webTestClient.post()
+                .uri(endpoint)
+                .header("Content-Type", "application/json")
+                .bodyValue(asJson(EntityCreator.exchangeRequest()
+                    .from(Symbol.PLN)
+                    .to(Symbol.USD)
+                    .toSell(PLN)
+                    .build()).replace("USD", "usd").replace("PLN", "pln"))
+                .exchange()
+                .expectStatus().isOk()
+                .expectBody().json(expected);
+            // cache
+            WireMockExtension.verifyGet(0, URI_PATTERN.formatted(date));
+        }
+
         private String getTodayOrLastFriday() {
             var today = LocalDate.now();
             if (today.getDayOfWeek() == DayOfWeek.SATURDAY