diff --git a/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateProviderTests/ExchangeRateProviderTests.cs b/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateProviderTests/ExchangeRateProviderTests.cs
new file mode 100644
index 000000000..54e7ab23e
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateProviderTests/ExchangeRateProviderTests.cs
@@ -0,0 +1,73 @@
+using ExchangeRateUpdater;
+using ExchangeRateUpdater.Models;
+using ExchangeRateUpdater.Services;
+using Moq;
+using Xunit;
+
+namespace ExchangeRateUpdaterTests.ExchangeRateProviderTests
+{
+
+ public class ExchangeRateProviderTests
+ {
+ [Fact]
+ public async Task GetExchangeRatesAsync_ReturnsRatesFromService_WhenCurrenciesProvided()
+ {
+ // Arrange
+ var currencies = new[]
+ {
+ new Currency("CZK"),
+ new Currency("USD")
+ };
+
+ var expectedRates = new List<ExchangeRate>
+ {
+ new ExchangeRate(new Currency("CZK"), new Currency("USD"), 22.5m)
+ };
+
+ var serviceMock = new Mock<IExchangeRateProviderService>();
+ serviceMock.Setup(s => s.GetExchangeRateAsync(It.Is<IEnumerable<Currency>>(c => c.SequenceEqual(currencies))))
+ .ReturnsAsync(expectedRates);
+
+ var provider = new ExchangeRateProvider(serviceMock.Object);
+
+ // Act
+ var result = await provider.GetExchangeRatesAsync(currencies);
+
+ // Assert
+ Assert.NotNull(result);
+ Assert.Single(result);
+ Assert.Equal("USD", result.First().TargetCurrency.Code);
+ serviceMock.Verify(s => s.GetExchangeRateAsync(It.IsAny<IEnumerable<Currency>>()), Times.Once);
+ }
+
+ [Fact]
+ public async Task GetExchangeRatesAsync_ReturnsEmpty_WhenCurrencyListIsNull()
+ {
+ // Arrange
+ var serviceMock = new Mock<IExchangeRateProviderService>();
+ var provider = new ExchangeRateProvider(serviceMock.Object);
+
+ // Act
+ var result = await provider.GetExchangeRatesAsync(null);
+
+ // Assert
+ Assert.Empty(result);
+ serviceMock.Verify(s => s.GetExchangeRateAsync(It.IsAny<IEnumerable<Currency>>()), Times.Never);
+ }
+
+ [Fact]
+ public async Task GetExchangeRatesAsync_ReturnsEmpty_WhenCurrencyListIsEmpty()
+ {
+ // Arrange
+ var serviceMock = new Mock<IExchangeRateProviderService>();
+ var provider = new ExchangeRateProvider(serviceMock.Object);
+
+ // Act
+ var result = await provider.GetExchangeRatesAsync(new List<Currency>());
+
+ // Assert
+ Assert.Empty(result);
+ serviceMock.Verify(s => s.GetExchangeRateAsync(It.IsAny<IEnumerable<Currency>>()), Times.Never);
+ }
+ }
+}
diff --git a/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateProviderTests/Integration/ExchangeRateProviderIntegrationTests.cs b/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateProviderTests/Integration/ExchangeRateProviderIntegrationTests.cs
new file mode 100644
index 000000000..3e4cda4d4
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateProviderTests/Integration/ExchangeRateProviderIntegrationTests.cs
@@ -0,0 +1,90 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using ExchangeRateUpdater.Configuration;
+using ExchangeRateUpdater.Models;
+using ExchangeRateUpdater.Services;
+using ExchangeRateUpdaterTests.StartupTests;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using RichardSzalay.MockHttp;
+using Xunit;
+
+namespace ExchangeRateUpdater.Tests.Integration
+{
+ public class ExchangeRateProviderIntegrationTests
+ {
+ [Fact]
+ public async Task GetExchangeRatesAsync_ReturnsCombinedRates_FromAllFetchers()
+ {
+ // Arrange
+
+ var mockHttp = new MockHttpMessageHandler();
+
+ mockHttp.When("https://mock-daily")
+ .Respond("text/plain", @"
+ 11 Jun 2025 #123
+ Country|Currency|Amount|Code|Rate
+ United States|Dollar|1|USD|22,123");
+
+ mockHttp.When("https://mock-other")
+ .Respond("text/plain", @"
+ 11 Jun 2025 #123
+ Country|Currency|Amount|Code|Rate|Source
+ Switzerland|Franc|1|CHF|25,456|SNB");
+
+ var httpClient = mockHttp.ToHttpClient();
+
+ var inMemorySettings = new Dictionary<string, string>
+ {
+ ["CzechBankSettings:DailyRatesUrl"] = "https://mock-daily",
+ ["CzechBankSettings:OtherCurrencyRatesUrl"] = "https://mock-other",
+ ["CzechBankSettings:TimeoutSeconds"] = "10",
+ ["CzechBankSettings:RetryCount"] = "2"
+ };
+
+ var config = new ConfigurationBuilder()
+ .AddInMemoryCollection(inMemorySettings)
+ .Build();
+
+ var services = new ServiceCollection();
+ var startup = new StartupForTest(config);
+ startup.ConfigureServices(services);
+
+ services.AddSingleton(httpClient);
+
+ var provider = services.BuildServiceProvider();
+
+ var httpFactory = new TestHttpClientFactory(httpClient);
+ services.AddSingleton<IHttpClientFactory>(httpFactory);
+
+ var finalProvider = services.BuildServiceProvider();
+
+ var exchangeRateProvider = finalProvider.GetRequiredService<IExchangeRateProviderService>();
+
+ // Act
+ var currencies = new[] { new Currency("USD"), new Currency("CHF") };
+ var rates = await exchangeRateProvider.GetExchangeRateAsync(currencies);
+
+ // Assert
+ Assert.NotEmpty(rates);
+ Assert.Contains(rates, r => r.TargetCurrency.Code == "USD");
+ Assert.Contains(rates, r => r.TargetCurrency.Code == "CHF");
+ }
+
+ // IHttpClientFactory override
+ private class TestHttpClientFactory : IHttpClientFactory
+ {
+ private readonly HttpClient _client;
+
+ public TestHttpClientFactory(HttpClient client)
+ {
+ _client = client;
+ }
+
+ public HttpClient CreateClient(string name) => _client;
+ }
+ }
+}
diff --git a/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateUpdaterTests.csproj b/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateUpdaterTests.csproj
new file mode 100644
index 000000000..930ef3def
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/ExchangeRateUpdaterTests.csproj
@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+ <PropertyGroup>
+ <TargetFramework>net6.0</TargetFramework>
+ <IsPackable>false</IsPackable>
+ <ImplicitUsings>enable</ImplicitUsings>
+ <Nullable>enable</Nullable>
+ </PropertyGroup>
+
+ <ItemGroup>
+ <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.4" />
+ <PackageReference Include="Moq" Version="4.20.72" />
+ <PackageReference Include="xunit" Version="2.4.2" />
+ <PackageReference Include="xunit.runner.visualstudio" Version="2.4.2" />
+ <PackageReference Include="RichardSzalay.MockHttp" Version="7.0.0" />
+ </ItemGroup>
+
+ <ItemGroup>
+ <ProjectReference Include="..\Task\ExchangeRateUpdater.csproj" />
+ </ItemGroup>
+
+</Project>
\ No newline at end of file
diff --git a/jobs/Backend/ExchangeRateUpdaterTests/HttpClients/ExchangeRateFetcherTests.cs b/jobs/Backend/ExchangeRateUpdaterTests/HttpClients/ExchangeRateFetcherTests.cs
new file mode 100644
index 000000000..e692ec8a2
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/HttpClients/ExchangeRateFetcherTests.cs
@@ -0,0 +1,33 @@
+using ExchangeRateUpdater.Configuration;
+using ExchangeRateUpdater.HttpClients;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Moq;
+using RichardSzalay.MockHttp;
+using Xunit;
+
+namespace ExchangeRateUpdaterTests.HttpClients
+{
+ public class ExchangeRateFetcherTests
+ {
+ [Fact]
+ public async Task FetchAsync_ReturnsExpectedRawText()
+ {
+ var mockHttp = new MockHttpMessageHandler();
+ mockHttp.When("https://mock-daily")
+ .Respond("text/plain", "Mock CNB Data");
+ var mockLogger = new Mock<ILogger<DailyExchangeRateFetcher>>();
+
+ var httpClient = mockHttp.ToHttpClient();
+
+ var fetcher = new DailyExchangeRateFetcher(
+ httpClient,
+ Options.Create(new CzechBankSettings { DailyRatesUrl = "https://mock-daily" }),
+ mockLogger.Object
+ );
+
+ var result = await fetcher.FetchAsync();
+ Assert.Equal("Mock CNB Data", result);
+ }
+ }
+}
diff --git a/jobs/Backend/ExchangeRateUpdaterTests/Parsers/CzechNationalBankTextRateParserTests.cs b/jobs/Backend/ExchangeRateUpdaterTests/Parsers/CzechNationalBankTextRateParserTests.cs
new file mode 100644
index 000000000..5474d605b
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/Parsers/CzechNationalBankTextRateParserTests.cs
@@ -0,0 +1,104 @@
+using ExchangeRateUpdater.Models;
+using ExchangeRateUpdater.Parsers;
+using Microsoft.Extensions.Logging;
+using Moq;
+using Xunit;
+
+namespace ExchangeRateUpdater.Tests.Parsers
+{
+ public class CzechNationalBankTextRateParserTests
+ {
+ private readonly CzechNationalBankTextRateParser _parser;
+
+ public CzechNationalBankTextRateParserTests()
+ {
+ var mockLogger = new Mock<ILogger<CzechNationalBankTextRateParser>>();
+ _parser = new CzechNationalBankTextRateParser(5, mockLogger.Object);
+ }
+
+ [Fact]
+ public void Parse_ParsesValidLine_Correctly()
+ {
+ var raw = @"
+11 Jun 2025 #123
+Country|Currency|Amount|Code|Rate
+United States|Dollar|1|USD|22,123
+";
+
+ var filter = new List<Currency> { new Currency("USD") };
+ var result = _parser.Parse(raw, filter, new Currency("CZK")).ToList();
+
+ Assert.Single(result);
+ var rate = result[0];
+ Assert.Equal("CZK", rate.SourceCurrency.Code);
+ Assert.Equal("USD", rate.TargetCurrency.Code);
+ Assert.Equal(22.123m, rate.Value);
+ }
+
+ [Fact]
+ public void Parse_SkipsLines_WithTooFewColumns()
+ {
+ var raw = @"
+11 Jun 2025 #123
+Country|Currency|Amount|Code|Rate
+Broken|Line|Only|3
+United States|Dollar|1|USD|22,123
+";
+
+ var filter = new List<Currency> { new Currency("USD") };
+ var result = _parser.Parse(raw, filter, new Currency("CZK")).ToList();
+
+ Assert.Single(result);
+ Assert.Equal("USD", result[0].TargetCurrency.Code);
+ }
+
+ [Fact]
+ public void Parse_SkipsCurrencies_NotInFilter()
+ {
+ var raw = @"
+11 Jun 2025 #123
+Country|Currency|Amount|Code|Rate
+United States|Dollar|1|USD|22,123
+Eurozone|Euro|1|EUR|25,456
+";
+
+ var filter = new List<Currency> { new Currency("EUR") };
+ var result = _parser.Parse(raw, filter, new Currency("CZK")).ToList();
+
+ Assert.Single(result);
+ Assert.Equal("EUR", result[0].TargetCurrency.Code);
+ }
+
+ [Fact]
+ public void Parse_NormalizesRate_BasedOnAmount()
+ {
+ var raw = @"
+11 Jun 2025 #123
+Country|Currency|Amount|Code|Rate
+Japan|Yen|100|JPY|50,000
+";
+
+ var filter = new List<Currency> { new Currency("JPY") };
+ var result = _parser.Parse(raw, filter, new Currency("CZK")).ToList();
+
+ Assert.Single(result);
+ Assert.Equal("JPY", result[0].TargetCurrency.Code);
+ Assert.Equal(0.500, (double)result[0].Value); // 50,000 / 100
+ }
+
+ [Fact]
+ public void Parse_ReturnsEmpty_WhenNoLinesMatch()
+ {
+ var raw = @"
+11 Jun 2025 #123
+Country|Currency|Amount|Code|Rate
+United States|Dollar|1|USD|22,123
+";
+
+ var filter = new List<Currency> { new Currency("EUR") }; // no EUR present
+ var result = _parser.Parse(raw, filter, new Currency("CZK")).ToList();
+
+ Assert.Empty(result);
+ }
+ }
+}
\ No newline at end of file
diff --git a/jobs/Backend/ExchangeRateUpdaterTests/ProviderServiceTests/ExchangeRateProviderServiceTests.cs b/jobs/Backend/ExchangeRateUpdaterTests/ProviderServiceTests/ExchangeRateProviderServiceTests.cs
new file mode 100644
index 000000000..e67774b82
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/ProviderServiceTests/ExchangeRateProviderServiceTests.cs
@@ -0,0 +1,123 @@
+using ExchangeRateUpdater.Configuration;
+using ExchangeRateUpdater.HttpClients;
+using ExchangeRateUpdater.Models;
+using ExchangeRateUpdater.Parsers;
+using ExchangeRateUpdater.Services;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Moq;
+using RichardSzalay.MockHttp;
+using Xunit;
+
+namespace ExchangeRateUpdater.Tests
+{
+ public class ExchangeRateProviderServiceTests
+ {
+ [Fact]
+ public async Task GetExchangeRateAsync_ReturnsRates_FromMultipleFetchers()
+ {
+ // Arrange
+ var provider = CreateProviderWithError(dailyFails: false, otherFails: false);
+
+ var currencies = new[]
+ {
+ new Currency("USD"),
+ new Currency("CHF")
+ };
+
+ // Act
+ var rates = await provider.GetExchangeRateAsync(currencies);
+
+ // Assert
+ Assert.NotEmpty(rates);
+ Assert.Contains(rates, r => r.TargetCurrency.Code == "USD");
+ Assert.Contains(rates, r => r.TargetCurrency.Code == "CHF");
+ }
+
+ [Fact]
+ public async Task GetExchangeRateAsync_FallbackToCache_WhenFetchFails()
+ {
+ // Arrange
+ var memoryCache = new MemoryCache(new MemoryCacheOptions());
+ var provider = CreateProviderWithError(dailyFails: false, otherFails: false, memoryCache);
+
+ var currencies = new[] { new Currency("USD") };
+
+ // Prime the cache
+ var initial = await provider.GetExchangeRateAsync(currencies);
+ Assert.NotEmpty(initial);
+
+ // Now simulate both fetchers failing
+ var providerWithFailure = CreateProviderWithError(
+ dailyFails: true,
+ otherFails: true,
+ memoryCache);
+
+ // Act
+ var fallbackResult = await providerWithFailure.GetExchangeRateAsync(currencies);
+
+ // Assert
+ Assert.NotEmpty(fallbackResult);
+ Assert.Equal(initial.Count, fallbackResult.Count); // cache fallback works
+ }
+
+ [Fact]
+ public async Task GetExchangeRateAsync_Throws_WhenNoCacheAndAllFetchersFail()
+ {
+ // Arrange
+ var provider = CreateProviderWithError(dailyFails: true, otherFails: true);
+
+ var requested = new[] { new Currency("USD") };
+
+ // Act & Assert
+ await Assert.ThrowsAsync<ApplicationException>(async() =>
+ {
+ await provider.GetExchangeRateAsync(requested);
+ });
+ }
+
+ private ExchangeRateProviderService CreateProviderWithError(bool dailyFails, bool otherFails, IMemoryCache memoryCache = null)
+ {
+ var mockHttp = new MockHttpMessageHandler();
+
+ if (dailyFails)
+ mockHttp.When("https://mock-daily").Respond(System.Net.HttpStatusCode.InternalServerError);
+ else
+ mockHttp.When("https://mock-daily").Respond("text/plain", "Country|Currency|Amount|Code|Rate\nDate\nUnited States|dollar|1|USD|22,345\n");
+
+ if (otherFails)
+ mockHttp.When("https://mock-other").Respond(System.Net.HttpStatusCode.InternalServerError);
+ else
+ mockHttp.When("https://mock-other").Respond("text/plain", "Country|Currency|Amount|Code|Rate|Source\nDate\nSwitzerland|franc|1|CHF|25,123|SNB\n");
+
+ var httpClient = mockHttp.ToHttpClient();
+
+ var mockDailyLogger = new Mock<ILogger<DailyExchangeRateFetcher>>();
+ var mockOtherLogger = new Mock<ILogger<OtherCurrencyExchangeRateFetcher>>();
+
+ var dailyFetcher = new DailyExchangeRateFetcher(
+ httpClient,
+ Options.Create(new CzechBankSettings { DailyRatesUrl = "https://mock-daily" }), mockDailyLogger.Object);
+
+ var otherFetcher = new OtherCurrencyExchangeRateFetcher(
+ httpClient,
+ Options.Create(new CzechBankSettings { OtherCurrencyRatesUrl = "https://mock-other" }), mockOtherLogger.Object);
+
+ var fetchers = new List<IExhangeRateFetcher> { dailyFetcher, otherFetcher };
+
+ var loggerFactory = LoggerFactory.Create(builder => builder.AddDebug());
+ var parserLogger = loggerFactory.CreateLogger<CzechNationalBankTextRateParser>();
+ var parser = new CzechNationalBankTextRateParser(5, parserLogger);
+
+ var providerLogger = loggerFactory.CreateLogger<ExchangeRateProviderService>();
+
+ return new ExchangeRateProviderService(
+ fetchers,
+ parser,
+ memoryCache ?? new MemoryCache(new MemoryCacheOptions()),
+ providerLogger
+ );
+ }
+ }
+}
\ No newline at end of file
diff --git a/jobs/Backend/ExchangeRateUpdaterTests/StartupTests/StartupForTests.cs b/jobs/Backend/ExchangeRateUpdaterTests/StartupTests/StartupForTests.cs
new file mode 100644
index 000000000..35760c318
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/StartupTests/StartupForTests.cs
@@ -0,0 +1,72 @@
+using ExchangeRateUpdater.Configuration;
+using ExchangeRateUpdater.HttpClients;
+using ExchangeRateUpdater.Parsers;
+using ExchangeRateUpdater.Services;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Polly;
+
+namespace ExchangeRateUpdaterTests.StartupTests
+{
+ public class StartupForTest : Startup
+ {
+ public new IConfiguration Configuration { get; }
+
+ public StartupForTest(IConfiguration configuration)
+ {
+ Configuration = configuration;
+ }
+
+ public new void ConfigureServices(IServiceCollection services)
+ {
+ services.Configure<CzechBankSettings>(Configuration.GetSection("CzechBankSettings"));
+
+ services.AddMemoryCache();
+ services.AddSingleton<IExchangeRateParser>(sp =>
+ new CzechNationalBankTextRateParser(5, sp.GetRequiredService<ILogger<CzechNationalBankTextRateParser>>()));
+
+ services.AddHttpClient<DailyExchangeRateFetcher>()
+ .ConfigureHttpClient((provider, client) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+ client.Timeout = TimeSpan.FromSeconds(settings.TimeoutSeconds);
+ })
+ .AddPolicyHandler((provider, request) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+ return Polly.Extensions.Http.HttpPolicyExtensions
+ .HandleTransientHttpError()
+ .WaitAndRetryAsync(settings.RetryCount,
+ retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));
+ });
+
+ services.AddHttpClient<OtherCurrencyExchangeRateFetcher>()
+ .ConfigureHttpClient((provider, client) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+ client.Timeout = TimeSpan.FromSeconds(settings.TimeoutSeconds);
+ })
+ .AddPolicyHandler((provider, request) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+ return Polly.Extensions.Http.HttpPolicyExtensions
+ .HandleTransientHttpError()
+ .WaitAndRetryAsync(settings.RetryCount,
+ retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));
+ });
+
+ services.AddSingleton<IExhangeRateFetcher, DailyExchangeRateFetcher>();
+ services.AddSingleton<IExhangeRateFetcher, OtherCurrencyExchangeRateFetcher>();
+ services.AddSingleton<IExchangeRateProviderService, ExchangeRateProviderService>();
+
+ services.AddLogging(logging =>
+ {
+ logging.ClearProviders();
+ logging.AddConfiguration(Configuration.GetSection("Logging"));
+ logging.AddConsole();
+ });
+ }
+ }
+}
diff --git a/jobs/Backend/ExchangeRateUpdaterTests/StartupTests/StartupTests.cs b/jobs/Backend/ExchangeRateUpdaterTests/StartupTests/StartupTests.cs
new file mode 100644
index 000000000..93af46cfa
--- /dev/null
+++ b/jobs/Backend/ExchangeRateUpdaterTests/StartupTests/StartupTests.cs
@@ -0,0 +1,81 @@
+using ExchangeRateUpdater.Configuration;
+using ExchangeRateUpdater.HttpClients;
+using ExchangeRateUpdater.Models;
+using ExchangeRateUpdater.Parsers;
+using ExchangeRateUpdater.Services;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Xunit;
+
+namespace ExchangeRateUpdaterTests.StartupTests
+{
+ public class StartupTests
+ {
+ [Fact]
+ public void ConfigureServices_RegistersDependenciesCorrectly()
+ {
+ var startup = new Startup();
+ var services = new ServiceCollection();
+ startup.ConfigureServices(services);
+
+ var provider = services.BuildServiceProvider();
+
+ var providerService = provider.GetRequiredService<IExchangeRateProviderService>();
+ Assert.NotNull(providerService);
+
+ var cache = provider.GetRequiredService<IMemoryCache>();
+ Assert.NotNull(cache);
+
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>();
+ Assert.NotNull(settings);
+ Assert.False(string.IsNullOrWhiteSpace(settings.Value.DailyRatesUrl));
+ Assert.False(string.IsNullOrWhiteSpace(settings.Value.OtherCurrencyRatesUrl));
+ Assert.True(settings.Value.TimeoutSeconds > 0);
+ Assert.True(settings.Value.RetryCount >= 0);
+
+ var parser = provider.GetRequiredService<IExchangeRateParser>();
+ Assert.NotNull(parser);
+
+ var fetchers = provider.GetServices<IExhangeRateFetcher>().ToList();
+ Assert.NotEmpty(fetchers);
+
+ bool hasDaily = fetchers.Any(f => f is DailyExchangeRateFetcher);
+ bool hasOther = fetchers.Any(f => f is OtherCurrencyExchangeRateFetcher);
+
+ Assert.True(hasDaily);
+ Assert.True(hasOther);
+
+ var httpFactory = provider.GetRequiredService<IHttpClientFactory>();
+ Assert.NotNull(httpFactory);
+
+ var loggerFactory = provider.GetRequiredService<ILoggerFactory>();
+ Assert.NotNull(loggerFactory);
+
+ var logger = loggerFactory.CreateLogger<StartupTests>();
+ Assert.NotNull(logger);
+ }
+
+ [Fact]
+ public async Task ConfigureServices_Throws_WhenUrlsAreMissing()
+ {
+ var config = new ConfigurationBuilder()
+ .AddInMemoryCollection(new Dictionary<string, string?>())
+ .Build();
+
+ var services = new ServiceCollection();
+
+ var startup = new StartupForTest(config);
+ startup.ConfigureServices(services);
+
+ var provider = services.BuildServiceProvider();
+ // Act + Assert: provider resolution should throw due to missing URLs
+ Assert.Throws<ArgumentNullException>(() =>
+ {
+ var _ = provider.GetRequiredService<IExchangeRateProviderService>();
+ });
+ }
+ }
+}
diff --git a/jobs/Backend/Task/.gitignore b/jobs/Backend/Task/.gitignore
new file mode 100644
index 000000000..dc661aeb1
--- /dev/null
+++ b/jobs/Backend/Task/.gitignore
@@ -0,0 +1,2 @@
+/.vs
+publish/
\ No newline at end of file
diff --git a/jobs/Backend/Task/CHANGELOG.md b/jobs/Backend/Task/CHANGELOG.md
new file mode 100644
index 000000000..fe76f0855
--- /dev/null
+++ b/jobs/Backend/Task/CHANGELOG.md
@@ -0,0 +1,47 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com),
+and this project adheres to [Semantic Versioning](https://semver.org).
+
+## [Unreleased]
+
+### Added
+- 2 HttpClients which fetch the Czech National Bank data sources
+- Parser for parsing data from the http call
+- Integration Test testing entire flow with mocked Http Responses
+- The `CHANGELOG` file itself
+- `Deployment.md` and `Dockerfile` for deployment steps
+- Detailed `README` file
+
+### Fixed
+- Single Responsibility Principle was being violated by the `ExchangeRateProviderService`
+- Moved the `ExchangeRateProvider` to Services folder keeping root clean
+- Unit tests which were failing from the new `ExchangeRateProvider` implementation
+- csproj organisation and using .net 9 packages on a project with target of .net 6
+- `appsettings` to folow the removal of `HttpServiceSettings`
+- Use Dependency Injection on `Program.cs`
+- Spelling mistake in test file name
+- Git ignore the publish folder
+
+### Removed
+- `HttpServiceSettings`; moved into the `CzechBankSettings`
+
+---
+
+## [1.0.0] - 2025-05-22
+
+### Added
+- Initial implementation of `ExchangeRateProvider`
+- Fetch rates from CNB daily and other endpoints
+- Dependency injection setup in console app
+- Logging and configuration via `appsettings.json`
+- HTTP timeout and retry support via Polly, configurable from appsettings
+- Unit tests for `ExchangeRateProvider`
+- Structured logging using Microsoft.Extensions.Logging
+- Cache fallback logic
+
+### Fixed
+- PlatformNotSupportedException from EventLog on non-Windows systems
+- ArgumentOutOfRangeException for timeout value
diff --git a/jobs/Backend/Task/Configuration/CzechBankSettings.cs b/jobs/Backend/Task/Configuration/CzechBankSettings.cs
new file mode 100644
index 000000000..fec7ae7d2
--- /dev/null
+++ b/jobs/Backend/Task/Configuration/CzechBankSettings.cs
@@ -0,0 +1,10 @@
+namespace ExchangeRateUpdater.Configuration
+{
+ public class CzechBankSettings
+ {
+ public string DailyRatesUrl { get; set; }
+ public string OtherCurrencyRatesUrl { get; set; }
+ public int TimeoutSeconds { get; set; } = 10;
+ public int RetryCount { get; set; } = 3;
+ }
+}
diff --git a/jobs/Backend/Task/Configuration/Startup.cs b/jobs/Backend/Task/Configuration/Startup.cs
new file mode 100644
index 000000000..d802d2237
--- /dev/null
+++ b/jobs/Backend/Task/Configuration/Startup.cs
@@ -0,0 +1,95 @@
+using System;
+using ExchangeRateUpdater.Services;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Polly.Extensions.Http;
+using Polly;
+using ExchangeRateUpdater.Parsers;
+using ExchangeRateUpdater.HttpClients;
+
+namespace ExchangeRateUpdater.Configuration
+{
+ public class Startup
+ {
+ public IConfiguration Configuration { get; }
+
+ public Startup()
+ {
+ var builder = new ConfigurationBuilder()
+ .AddJsonFile("appsettings.json", optional: false);
+
+ Configuration = builder.Build();
+ }
+
+ public void ConfigureServices(IServiceCollection services)
+ {
+ // Bind configurations
+ services.Configure<CzechBankSettings>(Configuration.GetSection("CzechBankSettings"));
+ services.AddSingleton<ExchangeRateProvider>();
+
+
+ // Add dependencies
+ services.AddMemoryCache();
+
+ // Register the parser
+ services.AddSingleton<IExchangeRateParser>(sp => new CzechNationalBankTextRateParser(5,
+ sp.GetRequiredService<ILogger<CzechNationalBankTextRateParser>>()));
+
+ // === Add resilient HTTP clients with Polly ===
+ services.AddHttpClient<DailyExchangeRateFetcher>()
+ .ConfigureHttpClient((provider, client) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+ client.Timeout = TimeSpan.FromSeconds(settings.TimeoutSeconds);
+ })
+ .AddPolicyHandler((provider, request) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+
+ return HttpPolicyExtensions
+ .HandleTransientHttpError()
+ .WaitAndRetryAsync(
+ retryCount: settings.RetryCount,
+ sleepDurationProvider: retryAttempt =>
+ TimeSpan.FromSeconds(Math.Pow(2, retryAttempt))
+ );
+ });
+
+ services.AddHttpClient<OtherCurrencyExchangeRateFetcher>()
+ .ConfigureHttpClient((provider, client) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+ client.Timeout = TimeSpan.FromSeconds(settings.TimeoutSeconds);
+ })
+ .AddPolicyHandler((provider, request) =>
+ {
+ var settings = provider.GetRequiredService<IOptions<CzechBankSettings>>().Value;
+
+ return HttpPolicyExtensions
+ .HandleTransientHttpError()
+ .WaitAndRetryAsync(
+ retryCount: settings.RetryCount,
+ sleepDurationProvider: retryAttempt =>
+ TimeSpan.FromSeconds(Math.Pow(2, retryAttempt))
+ );
+ });
+
+ // Register fetchers
+ services.AddSingleton<IExhangeRateFetcher, DailyExchangeRateFetcher>();
+ services.AddSingleton<IExhangeRateFetcher, OtherCurrencyExchangeRateFetcher>();
+
+ // Register main provider
+ services.AddSingleton<IExchangeRateProviderService, ExchangeRateProviderService>();
+
+ // Add logging
+ services.AddLogging(logging =>
+ {
+ logging.ClearProviders();
+ logging.AddConfiguration(Configuration.GetSection("Logging"));
+ logging.AddConsole();
+ });
+ }
+ }
+}
diff --git a/jobs/Backend/Task/Dockerfile b/jobs/Backend/Task/Dockerfile
new file mode 100644
index 000000000..5acbc69b7
--- /dev/null
+++ b/jobs/Backend/Task/Dockerfile
@@ -0,0 +1,8 @@
+# Use official .NET runtime image
+FROM mcr.microsoft.com/dotnet/runtime:6.0
+
+WORKDIR /app
+
+COPY ./publish/ .
+
+ENTRYPOINT ["dotnet", "ExchangeRateUpdater.dll"]
diff --git a/jobs/Backend/Task/ExchangeRateProvider.cs b/jobs/Backend/Task/ExchangeRateProvider.cs
deleted file mode 100644
index 6f82a97fb..000000000
--- a/jobs/Backend/Task/ExchangeRateProvider.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-using System.Collections.Generic;
-using System.Linq;
-
-namespace ExchangeRateUpdater
-{
- public class ExchangeRateProvider
- {
- /// <summary>
- /// Should return exchange rates among the specified currencies that are defined by the source. But only those defined
- /// by the source, do not return calculated exchange rates. E.g. if the source contains "CZK/USD" but not "USD/CZK",
- /// do not return exchange rate "USD/CZK" with value calculated as 1 / "CZK/USD". If the source does not provide
- /// some of the currencies, ignore them.
- /// </summary>
- public IEnumerable<ExchangeRate> GetExchangeRates(IEnumerable<Currency> currencies)
- {
- return Enumerable.Empty<ExchangeRate>();
- }
- }
-}
diff --git a/jobs/Backend/Task/ExchangeRateUpdater.csproj b/jobs/Backend/Task/ExchangeRateUpdater.csproj
index 2fc654a12..b2359b985 100644
--- a/jobs/Backend/Task/ExchangeRateUpdater.csproj
+++ b/jobs/Backend/Task/ExchangeRateUpdater.csproj
@@ -1,8 +1,29 @@
<Project Sdk="Microsoft.NET.Sdk">
- <PropertyGroup>
- <OutputType>Exe</OutputType>
- <TargetFramework>net6.0</TargetFramework>
- </PropertyGroup>
+ <PropertyGroup>
+ <OutputType>Exe</OutputType>
+ <TargetFramework>net6.0</TargetFramework>
+ <PublishSingleFile>true</PublishSingleFile>
+ <SelfContained>true</SelfContained>
+ <RuntimeIdentifier>win-x64</RuntimeIdentifier> <!-- or linux-x64 for Linux servers -->
+ </PropertyGroup>
+
+ <ItemGroup>
+ <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="6.0.3" />
+ <PackageReference Include="Microsoft.Extensions.Hosting" Version="6.0.1" />
+ <PackageReference Include="Microsoft.Extensions.Http" Version="6.0.1" />
+ <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="6.0.36" />
+ <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.1" />
+ <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="6.0.1" />
+ </ItemGroup>
+
+ <ItemGroup>
+ <None Update="appsettings.json">
+ <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+ </None>
+ <None Update="appsettings.development.json">
+ <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+ </None>
+ </ItemGroup>
</Project>
\ No newline at end of file
diff --git a/jobs/Backend/Task/ExchangeRateUpdater.sln b/jobs/Backend/Task/ExchangeRateUpdater.sln
index 89be84daf..03c459cd2 100644
--- a/jobs/Backend/Task/ExchangeRateUpdater.sln
+++ b/jobs/Backend/Task/ExchangeRateUpdater.sln
@@ -1,10 +1,19 @@
Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 14
-VisualStudioVersion = 14.0.25123.0
+# Visual Studio Version 17
+VisualStudioVersion = 17.12.35707.178
MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ExchangeRateUpdater", "ExchangeRateUpdater.csproj", "{7B2695D6-D24C-4460-A58E-A10F08550CE0}"
EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{FD84211C-7857-4F86-AF9D-8EF05EE3C34B}"
+ ProjectSection(SolutionItems) = preProject
+ .gitignore = .gitignore
+ CHANGELOG.md = CHANGELOG.md
+ README.md = README.md
+ EndProjectSection
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ExchangeRateUpdaterTests", "..\ExchangeRateUpdaterTests\ExchangeRateUpdaterTests.csproj", "{3F178CA6-0C53-4407-9285-6862F4A26158}"
+EndProject
Global
GlobalSection(SolutionConfigurationPlatforms) = preSolution
Debug|Any CPU = Debug|Any CPU
@@ -15,6 +24,10 @@ Global
{7B2695D6-D24C-4460-A58E-A10F08550CE0}.Debug|Any CPU.Build.0 = Debug|Any CPU
{7B2695D6-D24C-4460-A58E-A10F08550CE0}.Release|Any CPU.ActiveCfg = Release|Any CPU
{7B2695D6-D24C-4460-A58E-A10F08550CE0}.Release|Any CPU.Build.0 = Release|Any CPU
+ {3F178CA6-0C53-4407-9285-6862F4A26158}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {3F178CA6-0C53-4407-9285-6862F4A26158}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {3F178CA6-0C53-4407-9285-6862F4A26158}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {3F178CA6-0C53-4407-9285-6862F4A26158}.Release|Any CPU.Build.0 = Release|Any CPU
EndGlobalSection
GlobalSection(SolutionProperties) = preSolution
HideSolutionNode = FALSE
diff --git a/jobs/Backend/Task/Extensions/CurrencyExtensions.cs b/jobs/Backend/Task/Extensions/CurrencyExtensions.cs
new file mode 100644
index 000000000..646a287ac
--- /dev/null
+++ b/jobs/Backend/Task/Extensions/CurrencyExtensions.cs
@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using ExchangeRateUpdater.Models;
+
+namespace ExchangeRateUpdater.Extensions
+{
+ public static class CurrencyExtensions
+ {
+ /// <summary>
+ /// Checks if the list of Currency contains a currency with the given code.
+ /// </summary>
+ public static bool Contains(this IEnumerable<Currency> currencies, string currencyCode)
+ {
+ if (currencyCode is null)
+ throw new ArgumentNullException(nameof(currencyCode));
+
+ return currencies.Any(c =>
+ string.Equals(c.Code, currencyCode, StringComparison.OrdinalIgnoreCase));
+ }
+ }
+}
diff --git a/jobs/Backend/Task/HttpClients/DailyExchangeRateFetcher.cs b/jobs/Backend/Task/HttpClients/DailyExchangeRateFetcher.cs
new file mode 100644
index 000000000..0c81f7016
--- /dev/null
+++ b/jobs/Backend/Task/HttpClients/DailyExchangeRateFetcher.cs
@@ -0,0 +1,51 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using ExchangeRateUpdater.Configuration;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace ExchangeRateUpdater.HttpClients
+{
+ public class DailyExchangeRateFetcher : IExhangeRateFetcher
+ {
+ private readonly HttpClient _httpClient;
+ private readonly string _url;
+ private readonly ILogger<DailyExchangeRateFetcher> _logger;
+
+ public DailyExchangeRateFetcher(
+ HttpClient httpClient,
+ IOptions<CzechBankSettings> options,
+ ILogger<DailyExchangeRateFetcher> logger)
+ {
+ _httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));
+ _url = options.Value.DailyRatesUrl ?? throw new ArgumentNullException(nameof(options.Value.DailyRatesUrl));
+ _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+ }
+
+ public async Task<string> FetchAsync()
+ {
+ _logger.LogInformation("Fetching daily exchange rates from {Url}", _url);
+
+ try
+ {
+ var start = DateTimeOffset.UtcNow;
+
+ var response = await _httpClient.GetAsync(_url);
+ response.EnsureSuccessStatusCode();
+
+ var content = await response.Content.ReadAsStringAsync();
+
+ var duration = DateTimeOffset.UtcNow - start;
+ _logger.LogInformation("Fetched daily exchange rates in {Duration} ms", duration.TotalMilliseconds);
+
+ return content;
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex, "Error fetching daily exchange rates from {Url}", _url);
+ throw;
+ }
+ }
+ }
+}
diff --git a/jobs/Backend/Task/HttpClients/IExhangeRateFetcher.cs b/jobs/Backend/Task/HttpClients/IExhangeRateFetcher.cs
new file mode 100644
index 000000000..8a64c18c5
--- /dev/null
+++ b/jobs/Backend/Task/HttpClients/IExhangeRateFetcher.cs
@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ExchangeRateUpdater.HttpClients
+{
+ public interface IExhangeRateFetcher
+ {
+ Task<string> FetchAsync();
+ }
+}
diff --git a/jobs/Backend/Task/HttpClients/OtherCurrencyExchangeRateFetcher.cs b/jobs/Backend/Task/HttpClients/OtherCurrencyExchangeRateFetcher.cs
new file mode 100644
index 000000000..c2b45760b
--- /dev/null
+++ b/jobs/Backend/Task/HttpClients/OtherCurrencyExchangeRateFetcher.cs
@@ -0,0 +1,51 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using ExchangeRateUpdater.Configuration;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace ExchangeRateUpdater.HttpClients
+{
+ public class OtherCurrencyExchangeRateFetcher : IExhangeRateFetcher
+ {
+ private readonly HttpClient _httpClient;
+ private readonly string _url;
+ private readonly ILogger<OtherCurrencyExchangeRateFetcher> _logger;
+
+ public OtherCurrencyExchangeRateFetcher(
+ HttpClient httpClient,
+ IOptions<CzechBankSettings> options,
+ ILogger<OtherCurrencyExchangeRateFetcher> logger)
+ {
+ _httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));
+ _url = options.Value.OtherCurrencyRatesUrl ?? throw new ArgumentNullException(nameof(options.Value.OtherCurrencyRatesUrl));
+ _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+ }
+
+ public async Task<string> FetchAsync()
+ {
+ _logger.LogInformation("Fetching other currency exchange rates from {Url}", _url);
+
+ try
+ {
+ var start = DateTimeOffset.UtcNow;
+
+ var response = await _httpClient.GetAsync(_url);
+ response.EnsureSuccessStatusCode();
+
+ var content = await response.Content.ReadAsStringAsync();
+
+ var duration = DateTimeOffset.UtcNow - start;
+ _logger.LogInformation("Fetched other currency exchange rates in {Duration} ms", duration.TotalMilliseconds);
+
+ return content;
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex, "Error fetching other currency exchange rates from {Url}", _url);
+ throw;
+ }
+ }
+ }
+}
diff --git a/jobs/Backend/Task/Currency.cs b/jobs/Backend/Task/Models/Currency.cs
similarity index 89%
rename from jobs/Backend/Task/Currency.cs
rename to jobs/Backend/Task/Models/Currency.cs
index f375776f2..8336d740e 100644
--- a/jobs/Backend/Task/Currency.cs
+++ b/jobs/Backend/Task/Models/Currency.cs
@@ -1,4 +1,4 @@
-namespace ExchangeRateUpdater
+namespace ExchangeRateUpdater.Models
{
public class Currency
{
diff --git a/jobs/Backend/Task/ExchangeRate.cs b/jobs/Backend/Task/Models/ExchangeRate.cs
similarity index 93%
rename from jobs/Backend/Task/ExchangeRate.cs
rename to jobs/Backend/Task/Models/ExchangeRate.cs
index 58c5bb10e..2133586d4 100644
--- a/jobs/Backend/Task/ExchangeRate.cs
+++ b/jobs/Backend/Task/Models/ExchangeRate.cs
@@ -1,4 +1,4 @@
-namespace ExchangeRateUpdater
+namespace ExchangeRateUpdater.Models
{
public class ExchangeRate
{
diff --git a/jobs/Backend/Task/Parsers/CzechNationalBankTextRateParser.cs b/jobs/Backend/Task/Parsers/CzechNationalBankTextRateParser.cs
new file mode 100644
index 000000000..94c6729cb
--- /dev/null
+++ b/jobs/Backend/Task/Parsers/CzechNationalBankTextRateParser.cs
@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using ExchangeRateUpdater.Extensions;
+using ExchangeRateUpdater.Models;
+using Microsoft.Extensions.Logging;
+
+namespace ExchangeRateUpdater.Parsers
+{
+ public class CzechNationalBankTextRateParser : IExchangeRateParser
+ {
+ private readonly int _expectedColumns;
+ private readonly ILogger<CzechNationalBankTextRateParser> _logger;
+
+ public CzechNationalBankTextRateParser(int expectedColumns, ILogger<CzechNationalBankTextRateParser> logger)
+ {
+ _expectedColumns = expectedColumns;
+ _logger = logger;
+ }
+
+ public IEnumerable<ExchangeRate> Parse(string raw, IEnumerable<Currency> filter, Currency sourceCurrency)
+ {
+ var parsedRates = new List<ExchangeRate>();
+ var filterSet = new HashSet<string>(
+ filter.Select(c => c.Code),
+ StringComparer.OrdinalIgnoreCase);
+
+ var lines = raw.Split('\n', StringSplitOptions.RemoveEmptyEntries);
+ _logger.LogDebug("Parsing CNB text: total lines (including header): {LineCount}", lines.Length);
+
+ for (int i = 2; i < lines.Length; i++) // skip header + date line
+ {
+ var parts = lines[i].Split('|');
+
+ if (parts.Length < _expectedColumns)
+ {
+ _logger.LogWarning("Skipping line {LineIndex}: expected {ExpectedColumns} columns but got {ActualColumns}",
+ i, _expectedColumns, parts.Length);
+ continue;
+ }
+
+ string code = parts[3].Trim();
+ if (!filterSet.Contains(code))
+ {
+ _logger.LogDebug("Skipping currency {CurrencyCode} as it's not in the filter list.", code);
+ continue;
+ }
+
+ try
+ {
+ int amount = int.Parse(parts[2].Trim());
+ decimal rate = decimal.Parse(
+ parts[4].Trim().Replace(',', '.'),
+ CultureInfo.InvariantCulture);
+
+ decimal normalized = rate / amount;
+
+ var exchangeRate = new ExchangeRate(sourceCurrency, new Currency(code), normalized);
+ parsedRates.Add(exchangeRate);
+
+ _logger.LogDebug("Parsed: {Source}/{Target} = {Value}",
+ sourceCurrency, code, normalized);
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex, "Failed to parse line {LineIndex}: {LineContent}", i, lines[i]);
+ }
+ }
+
+ _logger.LogInformation("Finished parsing. Extracted {ParsedCount} exchange rates.", parsedRates.Count);
+ return parsedRates;
+ }
+ }
+}
diff --git a/jobs/Backend/Task/Parsers/IExchangeRateParser.cs b/jobs/Backend/Task/Parsers/IExchangeRateParser.cs
new file mode 100644
index 000000000..a8194d451
--- /dev/null
+++ b/jobs/Backend/Task/Parsers/IExchangeRateParser.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+using ExchangeRateUpdater.Models;
+
+namespace ExchangeRateUpdater.Parsers
+{
+ public interface IExchangeRateParser
+ {
+ IEnumerable<ExchangeRate> Parse(string content, IEnumerable<Currency> filter, Currency source);
+ }
+}
diff --git a/jobs/Backend/Task/Program.cs b/jobs/Backend/Task/Program.cs
index 379a69b1f..1e2b2c327 100644
--- a/jobs/Backend/Task/Program.cs
+++ b/jobs/Backend/Task/Program.cs
@@ -1,6 +1,12 @@
using System;
using System.Collections.Generic;
using System.Linq;
+using ExchangeRateUpdater.Configuration;
+using ExchangeRateUpdater.Models;
+using ExchangeRateUpdater.Services;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
namespace ExchangeRateUpdater
{
@@ -21,10 +27,20 @@ public static class Program
public static void Main(string[] args)
{
+ var startup = new Startup();
+
+ using IHost host = Host.CreateDefaultBuilder(args)
+ .ConfigureServices(startup.ConfigureServices)
+ .Build();
+
+ // Get services
+ var logger = host.Services.GetRequiredService<ILoggerFactory>()
+ .CreateLogger("Main");
+
try
{
- var provider = new ExchangeRateProvider();
- var rates = provider.GetExchangeRates(currencies);
+ var provider = host.Services.GetRequiredService<ExchangeRateProvider>();
+ var rates = provider.GetExchangeRatesAsync(currencies).Result;
Console.WriteLine($"Successfully retrieved {rates.Count()} exchange rates:");
foreach (var rate in rates)
diff --git a/jobs/Backend/Task/README.md b/jobs/Backend/Task/README.md
new file mode 100644
index 000000000..02d7e394f
--- /dev/null
+++ b/jobs/Backend/Task/README.md
@@ -0,0 +1,72 @@
+# CzechNationalBank ExchangeRateUpdater
+
+A robust .NET 6 console application that pulls daily and other currency exchange rates from the Czech National Bank, parses and caches them, and exposes a reusable provider for integration into other systems.
+
+---
+
+## Features
+
+- ✅ Fetches official CNB daily and other currency exchange rates
+- ✅ Handles parsing of CNB's custom text formats
+- ✅ Uses resilient HTTP client with Polly retry and timeout policies
+- ✅ Caches rates until the next official update (2:30 PM daily)
+- ✅ Fully unit-tested and integration-tested
+- ✅ Runs standalone or inside a Docker container
+
+---
+
+## Getting Started
+
+### Requirements
+
+- [.NET 6 SDK](https://dotnet.microsoft.com/download/dotnet/6.0)
+- [Docker Desktop](https://www.docker.com/products/docker-desktop) (optional)
+
+---
+
+### Build & Run Locally
+
+`bash`
+# Build & run
+dotnet build
+dotnet run --project ExchangeRateUpdater
+
+---
+
+## Run with Docker
+
+### Publish build
+dotnet publish -c Release -o ./publish
+
+### Build Docker image
+docker build -t exchangerate-updater .
+
+### Run in Docker
+docker run --rm exchangerate-updater
+
+---
+
+# Configuration
+The app reads from `appsettings.json`
+
+Override these settings at runtime with env variables eg:
+
+`docker run --rm -e CzechBankSettings__DailyRatesUrl=https://mock exchangerate-updater`
+
+---
+
+## Run Tests
+
+`dotnet test ExchangeRateUpdaterTests`
+
+---
+
+## Deployment
+
+See [deployment.md](./deployment.md) for detailed instructions
+
+---
+
+## Changelog
+
+[Changelog](./CHANGELOG.md)
\ No newline at end of file
diff --git a/jobs/Backend/Task/Services/ExchangeRateProvider.cs b/jobs/Backend/Task/Services/ExchangeRateProvider.cs
new file mode 100644
index 000000000..60d404c21
--- /dev/null
+++ b/jobs/Backend/Task/Services/ExchangeRateProvider.cs
@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using ExchangeRateUpdater.Models;
+
+namespace ExchangeRateUpdater.Services
+{
+ public class ExchangeRateProvider
+ {
+ private readonly IExchangeRateProviderService _service;
+
+ public ExchangeRateProvider(IExchangeRateProviderService service)
+ {
+ _service = service ?? throw new ArgumentNullException(nameof(service));
+ }
+
+ /// <summary>
+ /// Should return exchange rates among the specified currencies that are defined by the source. But only those defined
+ /// by the source, do not return calculated exchange rates. E.g. if the source contains "CZK/USD" but not "USD/CZK",
+ /// do not return exchange rate "USD/CZK" with value calculated as 1 / "CZK/USD". If the source does not provide
+ /// some of the currencies, ignore them.
+ /// </summary>
+ public async Task<IEnumerable<ExchangeRate>> GetExchangeRatesAsync(IEnumerable<Currency> currencies)
+ {
+ if (currencies == null || !currencies.Any())
+ {
+ return Enumerable.Empty<ExchangeRate>();
+ }
+ return await _service.GetExchangeRateAsync(currencies);
+ }
+ }
+}
diff --git a/jobs/Backend/Task/Services/ExchangeRateProviderService.cs b/jobs/Backend/Task/Services/ExchangeRateProviderService.cs
new file mode 100644
index 000000000..94d7a2bfd
--- /dev/null
+++ b/jobs/Backend/Task/Services/ExchangeRateProviderService.cs
@@ -0,0 +1,92 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+using ExchangeRateUpdater.HttpClients;
+using ExchangeRateUpdater.Models;
+using ExchangeRateUpdater.Parsers;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Logging;
+
+namespace ExchangeRateUpdater.Services
+{
+ public class ExchangeRateProviderService : IExchangeRateProviderService
+ {
+ private readonly IEnumerable<IExhangeRateFetcher> _fetchers;
+ private readonly IExchangeRateParser _parser;
+ private readonly ILogger<ExchangeRateProviderService> _logger;
+ private readonly IMemoryCache _cache;
+ private const string CacheKey = nameof(CacheKey);
+ private const string SourceCurrency = "CZK";
+
+ public ExchangeRateProviderService(
+ IEnumerable<IExhangeRateFetcher> fetchers,
+ IExchangeRateParser parser,
+ IMemoryCache cache,
+ ILogger<ExchangeRateProviderService> logger)
+ {
+ _fetchers = fetchers;
+ _parser = parser;
+ _cache = cache;
+ _logger = logger;
+ }
+
+ public async Task<List<ExchangeRate>> GetExchangeRateAsync(IEnumerable<Currency> currencies)
+ {
+ var targetCodes = new HashSet<string>(
+ currencies.Select(c => c.Code),
+ StringComparer.OrdinalIgnoreCase
+ );
+
+
+ if (_cache.TryGetValue(CacheKey, out List<ExchangeRate> cachedRates))
+ {
+ _logger.LogInformation("Returning filtered exchange rates from cache.");
+ return cachedRates
+ .Where(rate => targetCodes.Contains(rate.TargetCurrency.Code))
+ .ToList();
+ }
+
+ // Parallel fetch
+ var fetchTasks = _fetchers.Select(s => s.FetchAsync()).ToList();
+
+ string[] content;
+ try
+ {
+ content = await Task.WhenAll(fetchTasks);
+ }
+ catch (Exception ex)
+ {
+ _logger.LogError(ex, "One or more sources failed during fetch.");
+ // If we have fallback cache, return that:
+ if (_cache.TryGetValue(CacheKey, out List<ExchangeRate> fallback))
+ {
+ _logger.LogWarning("Returning cached rates due to fetch failure.");
+ return fallback.Where(rate => targetCodes.Contains(rate.TargetCurrency.Code)).ToList();
+ }
+
+ throw new ApplicationException("Failed to fetch exchange rates and no cached fallback is available.", ex);
+ }
+
+ var exchangeRates = new List<ExchangeRate>();
+ foreach (var raw in content)
+ {
+ exchangeRates.AddRange(_parser.Parse(raw, currencies, new Currency(SourceCurrency)));
+ }
+
+
+
+ var now = DateTimeOffset.UtcNow;
+ var nextUpdate = new DateTimeOffset(now.Date.AddHours(13.5)); // 2:30 PM CET Daily update according to their website
+ if (now >= nextUpdate) nextUpdate = nextUpdate.AddDays(1);
+
+ _cache.Set(CacheKey, exchangeRates, nextUpdate);
+
+ _logger.LogInformation("Successfully fetched exchange rates until {NextUpdate}.", nextUpdate);
+ return exchangeRates
+ .Where(rate => targetCodes.Contains(rate.TargetCurrency.Code))
+ .ToList();
+ }
+ }
+}
diff --git a/jobs/Backend/Task/Services/IExchangeRateProviderService.cs b/jobs/Backend/Task/Services/IExchangeRateProviderService.cs
new file mode 100644
index 000000000..09a9302d5
--- /dev/null
+++ b/jobs/Backend/Task/Services/IExchangeRateProviderService.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using ExchangeRateUpdater.Models;
+
+ namespace ExchangeRateUpdater.Services;
+
+public interface IExchangeRateProviderService
+{
+ Task<List<ExchangeRate>> GetExchangeRateAsync(IEnumerable<Currency> currencies);
+}
\ No newline at end of file
diff --git a/jobs/Backend/Task/appsettings.development.json b/jobs/Backend/Task/appsettings.development.json
new file mode 100644
index 000000000..4c8786c1a
--- /dev/null
+++ b/jobs/Backend/Task/appsettings.development.json
@@ -0,0 +1,13 @@
+{
+ "Logging": {
+ "LogLevel": {
+ "Default": "Debug"
+ }
+ },
+ "CzechBankSettings": {
+ "DailyRatesUrl": "https://www.cnb.cz/en/financial-markets/foreign-exchange-market/central-bank-exchange-rate-fixing/central-bank-exchange-rate-fixing/daily.txt",
+ "OtherCurrencyRatesUrl": "https://www.cnb.cz/en/financial-markets/foreign-exchange-market/fx-rates-of-other-currencies/fx-rates-of-other-currencies/fx_rates.txt",
+ "TimeoutSeconds": 10,
+ "RetryCount": 3
+ }
+}
\ No newline at end of file
diff --git a/jobs/Backend/Task/appsettings.json b/jobs/Backend/Task/appsettings.json
new file mode 100644
index 000000000..4fd3d6668
--- /dev/null
+++ b/jobs/Backend/Task/appsettings.json
@@ -0,0 +1,16 @@
+{
+ "Logging": {
+ "LogLevel": {
+ "Default": "Information",
+ "ExchangeRateUpdater": "Debug",
+ "Microsoft": "Warning",
+ "System": "Warning"
+ }
+ },
+ "CzechBankSettings": {
+ "DailyRatesUrl": "https://www.cnb.cz/en/financial-markets/foreign-exchange-market/central-bank-exchange-rate-fixing/central-bank-exchange-rate-fixing/daily.txt",
+ "OtherCurrencyRatesUrl": "https://www.cnb.cz/en/financial-markets/foreign-exchange-market/fx-rates-of-other-currencies/fx-rates-of-other-currencies/fx_rates.txt",
+ "TimeoutSeconds": 10,
+ "RetryCount": 3
+ }
+}
\ No newline at end of file
diff --git a/jobs/Backend/Task/deployment.md b/jobs/Backend/Task/deployment.md
new file mode 100644
index 000000000..a39d7222b
--- /dev/null
+++ b/jobs/Backend/Task/deployment.md
@@ -0,0 +1,12 @@
+# Deployment Guide: ExchangeRateUpdater
+
+This document explains how to deploy and run the Exchange Rate Updater console app in production.
+
+---
+
+## Build & Publish
+
+Publish as a **self-contained single file executable** for your target OS:
+
+```bash
+dotnet publish -c Release -r win-x64 --self-contained true -p:PublishSingleFile=true -o ./publish