Merge pull request 'Fixes after code review' from fixes into master

pom.xml

@@ -28,6 +28,7 @@
 
         <!-- dependencies -->
         <wiremock.version>3.5.4</wiremock.version>
+        <openapi.version>2.5.0</openapi.version>
 
         <!-- plugins -->
         <jsonschema2pojo.version>1.2.1</jsonschema2pojo.version>
@@ -62,6 +63,11 @@
             <artifactId>lombok</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springdoc</groupId>
+            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
+            <version>${openapi.version}</version>
+        </dependency>
 
         <!-- Database -->
         <dependency>
@@ -110,6 +116,7 @@
                 <configuration>
                     <sourceDirectory>${basedir}/src/main/resources/schema</sourceDirectory>
                     <targetPackage>eu.ztsh.wymiana.model</targetPackage>
+                    <useBigDecimals>true</useBigDecimals>
                 </configuration>
                 <executions>
                     <execution>

readme.md

@@ -28,16 +28,16 @@ Prosty mikroserwis stworzony na potrzeby rekrutacji
       "pesel": {
         "type": "string"
       },
-      "pln": {
+      "initial": {
         "type": "number",
-        "description": "początkowy stan konta w złotówkach"
+        "description": "początkowy stan konta w domyślnej walucie"
       }
     },
     "required": [
       "name",
       "surname",
       "pesel",
-      "pln"
+      "initial"
     ]
   }
   ```
@@ -79,7 +79,6 @@ Prosty mikroserwis stworzony na potrzeby rekrutacji
         "type": "string"
       },
       "currencies": {
-        "$comment": "TODO: Map -> List",
         "type": "array",
         "items": {
           "$ref": "#/def/currency"
@@ -169,6 +168,35 @@ Prosty mikroserwis stworzony na potrzeby rekrutacji
     actor <--> exchange
     endpoint <--> core
     core <--> tabC
-    core <-- hsql.port --> hsqldb
+    core <-- hsql . port --> hsqldb
 
 ```
+
+## Konfiguracja
+
+Aplikacja posiada dostosowaną konfigurację, która obejmuje własności:
+
+### `hsqldb`
+
+Konfiguracja bazy danych
+
+| Nazwa | Opis             | Typ    | Wartość domyślna |
+|-------|------------------|--------|------------------|
+| name  | host bazy danych | string | db               |
+| port  | port bazy danych | int    | 9090             |
+
+### `nbp`
+
+Konfiguracja połączenia z Narodowym Bankiem Polskim
+
+| Nazwa   | Opis         | Typ    | Wartość domyślna  |
+|---------|--------------|--------|-------------------|
+| baseurl | host API nbp | string | http://api.nbp.pl |
+
+### `currency`
+
+Konfiguracja walut
+
+| Nazwa   | Opis                                    | Typ    | Wartość domyślna |
+|---------|-----------------------------------------|--------|------------------|
+| initial | waluta początkowa przy zakładaniu konta | string | PLN              |

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

@@ -1,12 +1,17 @@
 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;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 
+import java.math.BigDecimal;
+
 @Data
 @NoArgsConstructor
 @AllArgsConstructor
@@ -17,7 +22,8 @@ public class CurrencyEntity {
     @Id
     String pesel;
     @Id
-    String symbol;
+    @Enumerated(EnumType.STRING)
-    Double amount;
+    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

@@ -1,5 +1,7 @@
 package eu.ztsh.wymiana.model;
 
-public record Currency(String symbol, double amount) {
+import java.math.BigDecimal;
+
+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 wrap(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;
@@ -28,59 +29,56 @@ 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(0D),
+                    Optional.ofNullable(request.toSell()).orElse(BigDecimal.ZERO),
-                    Optional.ofNullable(request.toBuy()).orElse(0D));
+                    Optional.ofNullable(request.toBuy()).orElse(BigDecimal.ZERO));
                 user.currencies().putAll(exchanged);
                 return userService.update(user);
             })
             .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(), 0D);
     }
 
-    private Map<String, Currency> performExchange(Currency from, Currency to, double toSell, double toBuy) {
+    private Map<Symbol, Currency> performExchange(Currency from, Currency to, BigDecimal toSell, BigDecimal toBuy) {
-        double exchangeRate;
+        BigDecimal exchangeRate;
-        double neededFromAmount;
+        BigDecimal neededFromAmount;
-        double requestedToAmount;
+        BigDecimal requestedToAmount;
-        if (from.symbol().equalsIgnoreCase("PLN")) {
+        if (from.symbol().equals(Symbol.PLN)) {
             exchangeRate = nbpService.getSellRate(to.symbol());
-            neededFromAmount = round(toBuy != 0 ? toBuy * exchangeRate : toSell);
+            neededFromAmount = round(toBuy.signum() != 0 ? toBuy.multiply(exchangeRate) : toSell);
-            requestedToAmount = round(toBuy != 0 ? toBuy : toSell / exchangeRate);
+            requestedToAmount = round(toBuy.signum() != 0 ? toBuy : divide(toSell, exchangeRate));
         } else {
             exchangeRate = nbpService.getBuyRate(from.symbol());
-            neededFromAmount = round(toBuy != 0 ? toBuy / exchangeRate : toSell);
+            neededFromAmount = round(toBuy.signum() != 0 ? divide(toBuy, exchangeRate) : toSell);
-            requestedToAmount = round(toBuy != 0 ? toBuy : toSell * exchangeRate);
+            requestedToAmount = round(toBuy.signum() != 0 ? toBuy : toSell.multiply(exchangeRate));
         }
-        if (neededFromAmount > from.amount()) {
+        if (neededFromAmount.compareTo(from.amount()) > 0) {
             throw new InsufficientFundsException();
         }
-        var newFrom = new Currency(from.symbol(), from.amount() - neededFromAmount);
+        var newFrom = new Currency(from.symbol(), from.amount().subtract(neededFromAmount));
-        var newTo = new Currency(to.symbol(), to.amount() + requestedToAmount);
+        var newTo = new Currency(to.symbol(), to.amount().add(requestedToAmount));
         return Stream.of(newFrom, newTo).collect(Collectors.toMap(Currency::symbol, currency -> currency));
     }
 
-    private double round(double input) {
+    private BigDecimal round(BigDecimal input) {
-        return BigDecimal.valueOf(input).setScale(2, RoundingMode.HALF_UP).doubleValue();
+        return input.setScale(2, RoundingMode.HALF_UP);
+    }
+
+    private BigDecimal divide(BigDecimal input, BigDecimal division) {
+        return input.setScale(2, RoundingMode.HALF_UP).divide(division, RoundingMode.HALF_UP);
     }
 
 }

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

@@ -2,12 +2,14 @@ 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;
 import org.springframework.stereotype.Service;
 import org.springframework.web.client.RestClient;
 
+import java.math.BigDecimal;
 import java.time.Clock;
 import java.time.DayOfWeek;
 import java.time.LocalDate;
@@ -28,28 +30,28 @@ 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 double getSellRate(String currency) {
+    public BigDecimal getSellRate(Symbol currency) {
-        return getCurrency(currency.toUpperCase()).sell();
+        return getCurrency(currency).sell();
     }
 
-    public double 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)) {
             var fresh = fetchData(currency, dtf.format(today));
-            var rate = fresh.getRates().get(0);
+            var rate = fresh.getRates().getFirst();
             cacheObject = new RatesCache(
                 LocalDate.parse(rate.getEffectiveDate(), dtf),
                 rate.getBid(),
                 rate.getAsk()
             );
-            cache.put(fresh.getCode(), cacheObject);
+            cache.put(Symbol.valueOf(fresh.getCode().toUpperCase()), cacheObject);
         }
         return cacheObject;
     }
@@ -68,8 +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);
@@ -82,7 +84,7 @@ public class NbpService {
             || today.getDayOfWeek() == DayOfWeek.SUNDAY;
     }
 
-    private record RatesCache(LocalDate date, double buy, double sell) {
+    private record RatesCache(LocalDate date, BigDecimal buy, BigDecimal sell) {
 
     }
 

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.wrap(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 +3,8 @@ 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 eu.ztsh.wymiana.web.model.UserResponse;
 
 import java.util.List;
 
@@ -19,9 +20,13 @@ public class UserMapper {
             CurrencyMapper.pojoMapToEntities(pojo.currencies(), pojo.pesel()));
     }
 
-    public static UserEntity requestToEntity(UserCreateRequest request) {
+    public static UserResponse pojoToResponse(User pojo) {
+        return new UserResponse(pojo.name(), pojo.surname(), pojo.pesel(), pojo.currencies().values().stream().toList());
+    }
+
+    public static UserEntity requestToEntity(UserCreateRequestConfiguredWrapper request) {
         return new UserEntity(request.pesel(), request.name(), request.surname(),
-            List.of(new CurrencyEntity(request.pesel(), "PLN", request.pln())));
+            List.of(new CurrencyEntity(request.pesel(), request.initialSymbol(), request.initial())));
     }
 
     private UserMapper() {

src/main/java/eu/ztsh/wymiana/validation/ValidExchangeRequestValidator.java

@@ -18,8 +18,8 @@ public class ValidExchangeRequestValidator implements
         return (request.from() != null && !request.from().equals(request.to()))
             && !((request.toBuy() == null && request.toSell() == null)
                 || (request.toBuy() != null && request.toSell() != null))
-            && ((request.toBuy() != null && request.toBuy() >= 0)
+            && ((request.toBuy() != null && request.toBuy().signum() >= 0)
-                || (request.toSell() != null && request.toSell() >= 0));
+                || (request.toSell() != null && request.toSell().signum() >= 0));
     }
 
 }

src/main/java/eu/ztsh/wymiana/web/controller/ExchangeController.java

@@ -4,9 +4,16 @@ import eu.ztsh.wymiana.exception.InsufficientFundsException;
 import eu.ztsh.wymiana.exception.UserNotFoundException;
 import eu.ztsh.wymiana.service.CurrencyService;
 import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
+import eu.ztsh.wymiana.web.model.UserResponse;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.PostMapping;
@@ -22,6 +29,22 @@ public class ExchangeController {
 
     private final CurrencyService currencyService;
 
+    @Operation(summary = "Perform exchange")
+    @ApiResponses(value = {
+        @ApiResponse(responseCode = "200",
+            description = "Exchange performed successfully",
+            content = @Content(mediaType = MediaType.APPLICATION_JSON_VALUE,
+                schema = @Schema(implementation = UserResponse.class))),
+        @ApiResponse(responseCode = "400",
+            description = "Insufficient funds",
+            content = @Content(mediaType = MediaType.TEXT_PLAIN_VALUE)),
+        @ApiResponse(responseCode = "404",
+            description = "User not found",
+            content = @Content(mediaType = MediaType.TEXT_PLAIN_VALUE)),
+        @ApiResponse(responseCode = "500",
+            description = "Another error has occurred",
+            content = @Content(mediaType = MediaType.TEXT_PLAIN_VALUE))
+    })
     @PostMapping
     public ResponseEntity<Object> exchange(@Valid @RequestBody CurrencyExchangeRequest request) {
         try {

src/main/java/eu/ztsh/wymiana/web/controller/UserController.java

@@ -2,14 +2,21 @@ package eu.ztsh.wymiana.web.controller;
 
 import eu.ztsh.wymiana.exception.UserAlreadyExistsException;
 import eu.ztsh.wymiana.exception.UserNotFoundException;
-import eu.ztsh.wymiana.model.User;
 import eu.ztsh.wymiana.service.UserService;
+import eu.ztsh.wymiana.util.UserMapper;
 import eu.ztsh.wymiana.validation.ValidationFailedException;
 import eu.ztsh.wymiana.web.model.UserCreateRequest;
+import eu.ztsh.wymiana.web.model.UserResponse;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
+import io.swagger.v3.oas.annotations.tags.Tag;
 import jakarta.validation.Valid;
 import jakarta.validation.ValidationException;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -23,14 +30,23 @@ import org.springframework.web.bind.annotation.RestController;
 @Validated
 @RestController
 @RequestMapping(path = "/api/user", produces = "application/json")
+@Tag(name="User management", description = "Create or get user")
 public class UserController {
 
     private final UserService userService;
 
+    @Operation(summary = "Get user by PESEL")
+    @ApiResponses(value = {
+        @ApiResponse(responseCode = "200", description = "User found"),
+        @ApiResponse(responseCode = "400", description = "Request not valid", content = @Content),
+        @ApiResponse(responseCode = "404", description = "User not found", content = @Content),
+        @ApiResponse(responseCode = "500", description = "Another error has occurred", content = @Content)
+    })
     @GetMapping("{pesel}")
-    public ResponseEntity<User> get(@PathVariable("pesel") String pesel) {
+    public ResponseEntity<UserResponse> get(@PathVariable("pesel") String pesel) {
         try {
             return userService.get(pesel)
+                .map(UserMapper::pojoToResponse)
                 .map(ResponseEntity::ok)
                 .orElseThrow(() -> new UserNotFoundException(pesel));
         } catch (Exception e) {
@@ -42,6 +58,13 @@ public class UserController {
         }
     }
 
+    @Operation(summary = "Create user")
+    @ApiResponses(value = {
+        @ApiResponse(responseCode = "204", description = "User created", content = @Content),
+        @ApiResponse(responseCode = "400", description = "Request not valid", content = @Content(mediaType = MediaType.TEXT_PLAIN_VALUE)),
+        @ApiResponse(responseCode = "409", description = "User already exists", content = @Content(mediaType = MediaType.TEXT_PLAIN_VALUE)),
+        @ApiResponse(responseCode = "500", description = "Another error has occurred", content = @Content(mediaType = MediaType.TEXT_PLAIN_VALUE))
+    })
     @PostMapping
     public ResponseEntity<String> create(@Valid @RequestBody UserCreateRequest request) {
         try {

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

@@ -1,18 +1,22 @@
 package eu.ztsh.wymiana.web.model;
 
+import eu.ztsh.wymiana.model.Symbol;
 import eu.ztsh.wymiana.validation.ValidExchangeRequest;
+import jakarta.validation.constraints.Min;
 import jakarta.validation.constraints.NotNull;
 import lombok.Builder;
 import org.hibernate.validator.constraints.pl.PESEL;
 
+import java.math.BigDecimal;
+
 @Builder
 @ValidExchangeRequest
 public record CurrencyExchangeRequest(
-    @PESEL String pesel,
+    @NotNull @PESEL String pesel,
-    @NotNull String from,
+    @NotNull Symbol from,
-    @NotNull String to,
+    @NotNull Symbol to,
-    Double toBuy,
+    @Min(0) BigDecimal toBuy,
-    Double toSell
+    @Min(0) BigDecimal toSell
 ) {
 
 }

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

@@ -6,11 +6,13 @@ import jakarta.validation.constraints.NotNull;
 import lombok.Builder;
 import org.hibernate.validator.constraints.pl.PESEL;
 
+import java.math.BigDecimal;
+
 @Builder
 public record UserCreateRequest(
     @NotNull String name,
     @NotNull String surname,
-    @PESEL @Adult String pesel,
+    @PESEL @Adult @NotNull String pesel,
-    @Min(0) double pln) {
+    @NotNull @Min(0) BigDecimal initial) {
 
 }

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

@@ -0,0 +1,9 @@
+package eu.ztsh.wymiana.web.model;
+
+import eu.ztsh.wymiana.model.Currency;
+
+import java.util.List;
+
+public record UserResponse(String name, String surname, String pesel, List<Currency> currencies) {
+
+}

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

@@ -5,10 +5,13 @@ 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;
 
+import java.math.BigDecimal;
+import java.math.RoundingMode;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -24,13 +27,11 @@ public class EntityCreator {
         public static String ANOTHER_PESEL = "08280959342";
         public static String NAME = "Janina";
         public static String SURNAME = "Kowalska";
-        public static double PLN = 20.10;
+        public static BigDecimal PLN = createScaled(20.10, 2);
-        public static double USD_SELL = 5.18;
+        public static BigDecimal USD_SELL = createScaled(5.18, 2);
-        public static double USD_BUY = 5.08;
+        public static BigDecimal USD_BUY = createScaled(5.08, 2);
-        public static String PLN_SYMBOL = "PLN";
+        public static BigDecimal BUY_RATE = createScaled(3.8804, 4);
-        public static String USD_SYMBOL = "USD";
+        public static BigDecimal SELL_RATE = createScaled(3.9572, 4);
-        public static double BUY_RATE = 3.8804;
-        public static double SELL_RATE = 3.9572;
 
     }
 
@@ -39,25 +40,29 @@ public class EntityCreator {
     }
 
     public static User user() {
-        return user(Constants.PLN, 0);
+        return user(Constants.PLN, BigDecimal.ZERO);
     }
 
-    public static User user(double pln, double usd) {
+    public static User user(BigDecimal pln, BigDecimal usd) {
-        Map<String, Currency> currencies = new HashMap<>();
+        Map<Symbol, Currency> currencies = new HashMap<>();
-        if (pln > 0) {
+        if (pln.signum() > 0) {
-            currencies.put("PLN", new Currency("PLN", pln));
+            currencies.put(Symbol.PLN, new Currency(Symbol.PLN, pln));
         }
-        if (usd > 0) {
+        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);
     }
 
     public static UserCreateRequest.UserCreateRequestBuilder userRequest() {
+        return userRequest(null);
+    }
+
+    public static UserCreateRequest.UserCreateRequestBuilder userRequest(Double initial) {
         return UserCreateRequest.builder().name(Constants.NAME)
             .surname(Constants.SURNAME)
             .pesel(Constants.PESEL)
-            .pln(Constants.PLN);
+            .initial(initial != null ? createScaled(initial, 2) : Constants.PLN);
     }
 
     public static CurrencyExchangeRequest.CurrencyExchangeRequestBuilder exchangeRequest() {
@@ -68,7 +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);
@@ -83,8 +88,8 @@ public class EntityCreator {
         String name;
         String surname;
         String pesel;
-        double pln = -1;
+        BigDecimal pln = BigDecimal.valueOf(-1);
-        double usd = -1;
+        BigDecimal usd = BigDecimal.valueOf(-1);
 
         public UserEntityBuilder name(String name) {
             this.name = name;
@@ -102,26 +107,34 @@ public class EntityCreator {
         }
 
         public UserEntityBuilder pln(double pln) {
-            this.pln = pln;
+            return this.pln(BigDecimal.valueOf(pln));
+        }
+
+        public UserEntityBuilder pln(BigDecimal pln) {
+            this.pln = pln.setScale(2, RoundingMode.HALF_UP);
             return this;
         }
 
         public UserEntityBuilder usd(double usd) {
-            this.usd = usd;
+            return this.usd(BigDecimal.valueOf(usd));
+        }
+
+        public UserEntityBuilder usd(BigDecimal usd) {
+            this.usd = usd.setScale(2, RoundingMode.HALF_UP);
             return this;
         }
 
         public UserEntity build() {
             var nonnulPesel = Optional.ofNullable(pesel).orElse(Constants.PESEL);
             List<CurrencyEntity> currencies = new ArrayList<>();
-            if (pln > -1) {
+            if (pln.signum() > -1) {
-                currencies.add(new CurrencyEntity(nonnulPesel, "PLN", pln));
+                currencies.add(new CurrencyEntity(nonnulPesel, Symbol.PLN, pln));
             }
-            if (usd > -1) {
+            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,
@@ -133,4 +146,8 @@ public class EntityCreator {
 
     }
 
+    private static BigDecimal createScaled(double input, int scale) {
+        return BigDecimal.valueOf(input).setScale(scale, RoundingMode.HALF_UP);
+    }
+
 }

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;
@@ -16,6 +17,8 @@ import org.junit.jupiter.params.provider.MethodSource;
 import org.mockito.Mockito;
 import org.springframework.beans.factory.annotation.Autowired;
 
+import java.math.BigDecimal;
+import java.util.Objects;
 import java.util.stream.Stream;
 
 import static eu.ztsh.wymiana.EntityCreator.Constants.*;
@@ -27,12 +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
@@ -41,12 +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() == 0 && 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), "USD 5.08");
         var expected = EntityCreator.userEntity().pln(0).usd(USD_BUY).build();
         expect(expected);
     }
@@ -57,12 +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() == 0 && 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);
     }
@@ -73,12 +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 -> map.get(PLN_SYMBOL).amount() == PLN && map.get(USD_SYMBOL).amount() == 0);
+            .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);
     }
@@ -89,12 +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 -> map.get(PLN_SYMBOL).amount() == PLN && map.get(USD_SYMBOL).amount() == 0);
+            .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);
     }
@@ -105,8 +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))
@@ -116,17 +121,17 @@ class CurrencyServiceTest extends RepositoryBasedTest {
     @Transactional
     @Test
     void doubleExchangeTest() {
-        var initialValue = 100;
+        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());
@@ -135,8 +140,8 @@ 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() < initialValue);
+            .findFirst()).isNotEmpty().get().matches(currencyEntity -> currencyEntity.getAmount().compareTo(initialValue) < 0);
     }
 
     @Transactional
@@ -145,8 +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))
@@ -159,8 +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))
@@ -171,8 +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))
@@ -183,7 +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))
@@ -195,7 +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
@@ -42,23 +44,22 @@ 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
     @DisplayName("Try to create another user with same PESEL")
     void createDuplicatedPeselTest() {
         var first = EntityCreator.userRequest().build();
-        var second = EntityCreator.userRequest()
+        var second = EntityCreator.userRequest(30.30)
-                .name("Jan")
+            .name("Jan")
-                .surname("Kowalski")
+            .surname("Kowalski")
-                .pln(30.30)
+            .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
@@ -66,8 +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
@@ -79,10 +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.wrap(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

@@ -1,14 +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 static eu.ztsh.wymiana.EntityCreator.Constants.PLN_SYMBOL;
+import java.math.BigDecimal;
+
 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> {
 
@@ -20,8 +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();
     }
@@ -30,8 +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();
     }
@@ -40,8 +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();
     }
@@ -50,8 +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();
     }
 
@@ -59,8 +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();
@@ -70,9 +71,9 @@ 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(-1.0)
+            .toBuy(BigDecimal.valueOf(-1.0))
             .build()).isFalse();
     }
 
@@ -80,9 +81,9 @@ 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(-1.0)
+            .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;
@@ -18,6 +19,7 @@ import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.web.reactive.server.WebTestClient;
 
+import java.math.BigDecimal;
 import java.time.DayOfWeek;
 import java.time.LocalDate;
 import java.time.format.DateTimeFormatter;
@@ -80,7 +82,7 @@ class ApplicationIntegrationTests {
         void createUserTest() {
             webTestClient.post()
                 .uri(endpoint)
-                .bodyValue(EntityCreator.userRequest().pln(100).build())
+                .bodyValue(EntityCreator.userRequest(100D).build())
                 .exchange()
                 .expectStatus().isNoContent();
         }
@@ -114,7 +116,7 @@ class ApplicationIntegrationTests {
                 .uri(endpoint.concat("/").concat(PESEL))
                 .exchange()
                 .expectStatus().isOk()
-                .expectBody().json(asJson(UserMapper.entityToPojo(EntityCreator.userEntity().pln(100).build())));
+                .expectBody().json(asJson(UserMapper.pojoToResponse(UserMapper.entityToPojo(EntityCreator.userEntity().pln(100).build()))));
         }
 
         @Test
@@ -152,8 +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()
@@ -169,12 +171,12 @@ class ApplicationIntegrationTests {
                 200,
                 asJson(EntityCreator.rates(date))
             );
-            var expected = asJson(EntityCreator.user(100 - PLN, USD_BUY));
+            var expected = asJson(EntityCreator.user(BigDecimal.valueOf(100).subtract(PLN), USD_BUY));
             webTestClient.post()
                 .uri(endpoint)
                 .bodyValue(EntityCreator.exchangeRequest()
-                    .from(PLN_SYMBOL)
+                    .from(Symbol.PLN)
-                    .to(USD_SYMBOL)
+                    .to(Symbol.USD)
                     .toSell(PLN)
                     .build())
                 .exchange()
@@ -190,8 +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()
@@ -206,8 +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()
@@ -220,14 +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