Configure warnings as errors and fix resulting errors

jobs/Backend/Task/ExchangeRateProvider/Directory.Build.props

@@ -0,0 +1,5 @@
+<Project>
+  <PropertyGroup>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+  </PropertyGroup>
+</Project>

jobs/Backend/Task/ExchangeRateProvider/src/ExchangeRateProvider.Api/Controllers/ExchangeRateController.cs

@@ -29,6 +29,9 @@ public async Task<ActionResult<IEnumerable<ExchangeRateDto>>> GetByCurrency(
             [FromQuery] List<string>? quoteCurrencies,
             CancellationToken cancellationToken = default)
         {
+            logger.LogInformation("Received request to get exchange rates. BaseCurrency: {BaseCurrency}, QuoteCurrencies: {QuoteCurrencies}",
+                baseCurrency, quoteCurrencies is not null ? string.Join(", ", quoteCurrencies) : "null");
+
             if (string.IsNullOrWhiteSpace(baseCurrency))
             {
                 return BadRequest(new ProblemDetails

jobs/Backend/Task/ExchangeRateProvider/src/ExchangeRateProvider.Infrastructure/ExternalServices/CZK/CzkExchangeRateService.cs

@@ -9,6 +9,8 @@ public class CzkExchangeRateService(HttpClient httpClient, ILogger<CzkExchangeRa
 {
     public async Task<IList<ExchangeRate>>GetExchangeRatesAsync(Currency baseCurrency, CancellationToken cancellationToken = default)
     {
+        logger.LogInformation("Fetching CZK exchange rates from external service.");
+
         var response = await httpClient.GetAsync(new Uri("https://api.cnb.cz/cnbapi/exrates/daily?lang=EN"), cancellationToken);
         response.EnsureSuccessStatusCode();
 

jobs/Backend/Task/ExchangeRateProvider/tests/ExchangeRateProvider.Api.Tests.Unit/Controllers/ExchangeRateControllerTests.cs

@@ -68,7 +68,7 @@ public async Task GetByCurrency_WithQuoteCurrencies_PassesThemToHandlerAndReturn
         A.CallTo(() => _fakeHandler.HandleAsync(
             A<GetExchangeRatesQuery>.That.Matches(q =>
                 q.BaseCurrency.Code == baseCurrency &&
-                q.QuoteCurrencies.Count == 2 &&
+                q.QuoteCurrencies!.Count == 2 &&
                 q.QuoteCurrencies.Any(c => c.Code == "EUR") &&
                 q.QuoteCurrencies.Any(c => c.Code == "GBP")),
             A<CancellationToken>._))
@@ -84,8 +84,8 @@ public async Task GetByCurrency_WithQuoteCurrencies_PassesThemToHandlerAndReturn
 
         A.CallTo(() => _fakeHandler.HandleAsync(
             A<GetExchangeRatesQuery>.That.Matches(q =>
-                q.QuoteCurrencies.Any(c => c.Code == "EUR") &&
-                q.QuoteCurrencies.Any(c => c.Code == "GBP")),
+                q.QuoteCurrencies!.Any(c => c.Code == "EUR") &&
+                q.QuoteCurrencies!.Any(c => c.Code == "GBP")),
             A<CancellationToken>._))
             .MustHaveHappenedOnceExactly();
     }
@@ -161,8 +161,8 @@ public async Task GetByCurrency_WithUnsupportedBaseCurrency_ReturnsBadRequest()
 
         var problemDetails = badRequestResult.Value.ShouldBeOfType<ProblemDetails>();
         problemDetails.Title.ShouldBe("Unsupported base currency");
-        problemDetails.Detail.ShouldContain($"The currency '{unsupportedCurrency}' is not supported");
-        problemDetails.Detail.ShouldContain("Supported currencies:");
+        problemDetails.Detail!.ShouldContain($"The currency '{unsupportedCurrency}' is not supported");
+        problemDetails.Detail!.ShouldContain("Supported currencies:");
         problemDetails.Status.ShouldBe(StatusCodes.Status400BadRequest);
 
         A.CallTo(() => _fakeHandler.HandleAsync(A<GetExchangeRatesQuery>._, A<CancellationToken>._))
@@ -206,7 +206,7 @@ public async Task GetByCurrency_WithQuoteCurrenciesContainingEmptyStrings_Filter
         A.CallTo(() => _fakeHandler.HandleAsync(
             A<GetExchangeRatesQuery>.That.Matches(q =>
                 q.BaseCurrency.Code == baseCurrency &&
-                q.QuoteCurrencies.Count == 2),
+                q.QuoteCurrencies!.Count == 2),
             A<CancellationToken>._))
             .Returns(expectedRates);
 
@@ -218,7 +218,7 @@ public async Task GetByCurrency_WithQuoteCurrenciesContainingEmptyStrings_Filter
 
         A.CallTo(() => _fakeHandler.HandleAsync(
             A<GetExchangeRatesQuery>.That.Matches(q =>
-                q.QuoteCurrencies.Count == 2 &&
+                q.QuoteCurrencies!.Count == 2 &&
                 q.QuoteCurrencies.All(c => !string.IsNullOrWhiteSpace(c.Code))),
             A<CancellationToken>._))
             .MustHaveHappenedOnceExactly();
@@ -277,8 +277,8 @@ public async Task GetByCurrency_WithLowercaseQuoteCurrencies_ConvertsToUppercase
 
         A.CallTo(() => _fakeHandler.HandleAsync(
             A<GetExchangeRatesQuery>.That.Matches(q =>
-                q.QuoteCurrencies.Any(c => c.Code == "EUR") &&
-                q.QuoteCurrencies.Any(c => c.Code == "GBP")),
+                q.QuoteCurrencies!.Any(c => c.Code == "EUR") &&
+                q.QuoteCurrencies!.Any(c => c.Code == "GBP")),
             A<CancellationToken>._))
             .MustHaveHappenedOnceExactly();
     }
@@ -328,7 +328,7 @@ public async Task GetByCurrency_WithValidThreeLetterQuoteCurrencies_PassesValida
         result.Result.ShouldBeOfType<OkObjectResult>();
 
         A.CallTo(() => _fakeHandler.HandleAsync(
-            A<GetExchangeRatesQuery>.That.Matches(q => q.QuoteCurrencies.Count == 4),
+            A<GetExchangeRatesQuery>.That.Matches(q => q.QuoteCurrencies!.Count == 4),
             A<CancellationToken>._))
             .MustHaveHappenedOnceExactly();
     }
@@ -357,7 +357,7 @@ public async Task GetByCurrency_WithMixedCaseValidQuoteCurrencies_ConvertsToUppe
 
         A.CallTo(() => _fakeHandler.HandleAsync(
             A<GetExchangeRatesQuery>.That.Matches(q =>
-                q.QuoteCurrencies.Count == 3 &&
+                q.QuoteCurrencies!.Count == 3 &&
                 q.QuoteCurrencies.All(c => c.Code == c.Code.ToUpperInvariant())),
             A<CancellationToken>._))
             .MustHaveHappenedOnceExactly();

jobs/Backend/Task/ExchangeRateProvider/tests/ExchangeRateProvider.Domain.Tests.Unit/Constants/CurrencyServiceKeysTests.cs

@@ -24,7 +24,6 @@ public void IsSupported_WithUnsupportedCurrency_ReturnsFalse(string currencyCode
     }
 
     [Theory]
-    [InlineData(null)]
     [InlineData("")]
     [InlineData("   ")]
     public void IsSupported_WithNullOrWhitespace_ReturnsFalse(string currencyCode)