Anton Miroshkin - Solution for Backend Task

.gitignore

@@ -21,3 +21,4 @@
 node_modules
 bower_components
 npm-debug.log
+/jobs/Backend/Task/.vs/ExchangeRateUpdater

jobs/Backend/Task.Tests/ExchangeRateUpdater.Tests/ExchangeRateProviderTests.cs

@@ -0,0 +1,230 @@
+using ExchangeRateUpdater.Cnb;
+using Microsoft.Extensions.Logging;
+using Moq;
+using Moq.Protected;
+using System.Net;
+using System.Text.Json.Serialization;
+
+namespace ExchangeRateUpdater.Tests
+{
+    public class ExchangeRateProviderTests : IDisposable
+    {
+        private readonly Mock<ILogger<ExchangeRateProvider>> _loggerMock;
+        private readonly Mock<IExchangeRateProviderConfiguration> _configMock;
+        private readonly Mock<HttpMessageHandler> _httpHandlerMock;
+        private readonly HttpClient _httpClient;
+
+        public ExchangeRateProviderTests()
+        {
+            _loggerMock = new Mock<ILogger<ExchangeRateProvider>>();
+            _configMock = new Mock<IExchangeRateProviderConfiguration>();
+            _httpHandlerMock = new Mock<HttpMessageHandler>();
+            _httpClient = new HttpClient(_httpHandlerMock.Object)
+            {
+                Timeout = TimeSpan.FromSeconds(1)
+            };
+
+            _configMock.SetupGet(c => c.Url).Returns("https://api.cnb.cz/cnbapi/exrates/daily");
+            _configMock.SetupGet(c => c.BaseCurrency).Returns("CZK");
+        }
+
+        [Fact]
+        public async Task GetExchangeRatesAsync_WithValidCurrencies_ReturnsExchangeRates()
+        {
+            // Arrange
+            var responseJson = "{" +
+                "\"rates\":[" +
+                    "{\"validFor\":\"2025-06-26\"," +
+                    "\"order\":121," +
+                    "\"country\":\"USA\"," +
+                    "\"currency\":\"dollar\"," +
+                    "\"amount\":1," +
+                    "\"currencyCode\":\"USD\"," +
+                    "\"rate\":23.50}," +
+                    "{\"validFor\":\"2025-06-26\"," +
+                    "\"order\":122," +
+                    "\"country\":\"EMU\"," +
+                    "\"currency\":\"euro\"," +
+                    "\"amount\":1," +
+                    "\"currencyCode\":\"EUR\"," +
+                    "\"rate\":25.75}" +
+                "]}";
+
+            SetupHttpResponse(HttpStatusCode.OK, responseJson);
+
+            var currencies = new List<Currency>
+            {
+                new Currency("USD"),
+                new Currency("EUR")
+            };
+
+            var provider = new ExchangeRateProvider(_configMock.Object, _httpClient);
+
+            // Act
+            var result = await provider.GetExchangeRatesAsync<CnbApiResponse>(currencies);
+
+            // Assert
+            Assert.NotNull(result);
+            var resultList = result.ToList();
+            Assert.Equal(2, resultList.Count);
+
+            var usdRate = resultList.FirstOrDefault(r => r.SourceCurrency.Code == "USD");
+            Assert.NotNull(usdRate);
+            Assert.Equal("USD", usdRate.SourceCurrency.Code);
+            Assert.Equal("CZK", usdRate.TargetCurrency.Code);
+            Assert.Equal(23.50m, usdRate.Value);
+
+            var eurRate = resultList.FirstOrDefault(r => r.SourceCurrency.Code == "EUR");
+            Assert.NotNull(eurRate);
+            Assert.Equal("EUR", eurRate.SourceCurrency.Code);
+            Assert.Equal("CZK", eurRate.TargetCurrency.Code);
+            Assert.Equal(25.75m, eurRate.Value);
+        }
+
+        [Fact]
+        public async Task GetExchangeRatesAsync_WithEmptyCurrencies_ReturnsEmptyResult()
+        {
+            // Arrange
+            var responseJson = "{\"rates\":[]}";
+            SetupHttpResponse(HttpStatusCode.OK, responseJson);
+
+            var currencies = new List<Currency>();
+            var provider = new ExchangeRateProvider(_configMock.Object, _httpClient);
+
+            // Act
+            var result = await provider.GetExchangeRatesAsync<CnbApiResponse>(currencies);
+
+            // Assert
+            Assert.NotNull(result);
+            Assert.Empty(result);
+        }
+
+        [Fact]
+        public async Task GetExchangeRatesAsync_WithNullCurrencies_ThrowsArgumentNullException()
+        {
+            // Arrange
+            var provider = new ExchangeRateProvider(_configMock.Object, _httpClient);
+
+            // Act & Assert
+            await Assert.ThrowsAsync<Exception>(() =>
+                provider.GetExchangeRatesAsync<CnbApiResponse>(null));
+        }
+
+        [Fact]
+        public async Task GetExchangeRatesAsync_WithUnavailableCurrency_ReturnsOnlyAvailableRates()
+        {
+            // Arrange
+            var responseJson = "{" +
+                "\"rates\":[" +
+                    "{\"validFor\":\"2025-06-26\"," +
+                    "\"order\":121," +
+                    "\"country\":\"USA\"," +
+                    "\"currency\":\"dollar\"," +
+                    "\"amount\":1," +
+                    "\"currencyCode\":\"USD\"," +
+                    "\"rate\":23.50}" +
+                "]}";
+
+            SetupHttpResponse(HttpStatusCode.OK, responseJson);
+
+            var currencies = new List<Currency>
+            {
+                new Currency("USD"),
+                new Currency("XYZ") // Non-existent currency
+            };
+
+            var provider = new ExchangeRateProvider(_configMock.Object, _httpClient);
+
+            // Act
+            var result = await provider.GetExchangeRatesAsync<CnbApiResponse>(currencies);
+
+            // Assert
+            Assert.NotNull(result);
+            var resultList = result.ToList();
+            Assert.Single(resultList);
+            Assert.Equal("USD", resultList.First().SourceCurrency.Code);
+        }
+
+        [Fact]
+        public async Task GetExchangeRatesAsync_WhenApiReturnsError_ThrowsException()
+        {
+            // Arrange
+            var errorJson = "{" +
+                "\"description\":\"API Error\"," +
+                "\"endPoint\":\"/cnbapi/exrates/daily\"," +
+                "\"errorCode\":\"INTERNAL_SERVER_ERROR\"," +
+                "\"happenedAt\":\"2025-06-26T10:37:28.547Z\"," +
+                "\"messageId\":\"abc123\"}";
+
+            SetupHttpResponse(HttpStatusCode.InternalServerError, errorJson);
+
+            var currencies = new List<Currency> { new Currency("USD") };
+            var provider = new ExchangeRateProvider(_configMock.Object, _httpClient);
+
+            // Act & Assert
+            await Assert.ThrowsAsync<Exception>(() =>
+                provider.GetExchangeRatesAsync<CnbApiResponse>(currencies));
+        }
+
+        [Fact]
+        public async Task GetExchangeRatesAsync_WhenNetworkFails_ThrowsException()
+        {
+            // Arrange
+            _httpHandlerMock.Protected()
+                .Setup<Task<HttpResponseMessage>>(
+                    "SendAsync",
+                    ItExpr.IsAny<HttpRequestMessage>(),
+                    ItExpr.IsAny<CancellationToken>()
+                )
+                .ThrowsAsync(new HttpRequestException("Network error"))
+                .Verifiable();
+
+            var currencies = new List<Currency> { new Currency("USD") };
+            var provider = new ExchangeRateProvider(_configMock.Object, _httpClient);
+
+            // Act & Assert
+            var exception = await Assert.ThrowsAsync<Exception>(() =>
+                provider.GetExchangeRatesAsync<CnbApiResponse>(currencies));
+
+            Assert.Contains("Network error", exception.Message);
+        }
+
+        [Fact]
+        public async Task GetExchangeRatesAsync_WithInvalidJson_ThrowsException()
+        {
+            // Arrange
+            var invalidJson = "{ invalid json structure";
+            SetupHttpResponse(HttpStatusCode.OK, invalidJson);
+
+            var currencies = new List<Currency> { new Currency("USD") };
+            var provider = new ExchangeRateProvider(_configMock.Object, _httpClient);
+
+            // Act & Assert
+            await Assert.ThrowsAsync<Exception>(() =>
+                provider.GetExchangeRatesAsync<CnbApiResponse>(currencies));
+        }
+
+        private void SetupHttpResponse(HttpStatusCode statusCode, string content)
+        {
+            var response = new HttpResponseMessage
+            {
+                StatusCode = statusCode,
+                Content = new StringContent(content, System.Text.Encoding.UTF8, "application/json")
+            };
+
+            _httpHandlerMock.Protected()
+                .Setup<Task<HttpResponseMessage>>(
+                    "SendAsync",
+                    ItExpr.IsAny<HttpRequestMessage>(),
+                    ItExpr.IsAny<CancellationToken>()
+                )
+                .ReturnsAsync(response)
+                .Verifiable();
+        }
+
+        public void Dispose()
+        {
+            _httpClient?.Dispose();
+        }
+    }
+}

jobs/Backend/Task.Tests/ExchangeRateUpdater.Tests/ExchangeRateUpdater.Tests.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.2" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\Task\ExchangeRateUpdater.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>

jobs/Backend/Task.Tests/ExchangeRateUpdater.Tests/ExchangeRateUpdater.Tests.sln

@@ -0,0 +1,24 @@
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.5.2.0
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ExchangeRateUpdater.Tests", "ExchangeRateUpdater.Tests.csproj", "{5CB870E0-6DD9-17C1-D2D3-F2421C52624D}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{5CB870E0-6DD9-17C1-D2D3-F2421C52624D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5CB870E0-6DD9-17C1-D2D3-F2421C52624D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5CB870E0-6DD9-17C1-D2D3-F2421C52624D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5CB870E0-6DD9-17C1-D2D3-F2421C52624D}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {5BAC1F21-3528-4D4A-BA6A-716F8EAA3048}
+	EndGlobalSection
+EndGlobal

jobs/Backend/Task/Cnb/ApiErrorResponse.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Text.Json.Serialization;
+
+namespace ExchangeRateUpdater.Cnb
+{
+    public class ApiErrorResponse
+    {
+        [JsonPropertyName("description")]
+        public string Description { get; set; }
+
+        [JsonPropertyName("endPoint")]
+        public string EndPoint { get; set; }
+
+        [JsonPropertyName("errorCode")]
+        public string ErrorCode { get; set; }
+
+        [JsonPropertyName("happenedAt")]
+        public DateTime HappenedAt { get; set; }
+
+        [JsonPropertyName("messageId")]
+        public string MessageId { get; set; }
+    }
+}

jobs/Backend/Task/Cnb/ApiResponse.cs

@@ -0,0 +1,9 @@
+namespace ExchangeRateUpdater.Cnb
+{
+    public class ApiResponse<T>
+    {
+        public bool Success { get; set; }
+        public T Data { get; set; }
+        public ApiErrorResponse Error { get; set; }
+    }
+}

jobs/Backend/Task/Cnb/CnbApiResponse.cs

@@ -0,0 +1,11 @@
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace ExchangeRateUpdater.Cnb
+{
+    public class CnbApiResponse
+    {
+        [JsonPropertyName("rates")]
+        public List<CnbRateDto> Rates { get; set; }
+    }
+}

jobs/Backend/Task/Cnb/CnbRateDto.cs

@@ -0,0 +1,16 @@
+using System.Text.Json.Serialization;
+
+namespace ExchangeRateUpdater.Cnb
+{
+    public class CnbRateDto
+    {
+        [JsonPropertyName("currencyCode")]
+        public string CurrencyCode { get; set; }
+
+        [JsonPropertyName("amount")]
+        public int Amount { get; set; }
+
+        [JsonPropertyName("rate")]
+        public decimal Rate { get; set; }
+    }
+}