btcpayserver/BTCPayServer.Tests/LanguageServiceTests.cs

using System.Threading.Tasks;
using BTCPayServer.Services;
using BTCPayServer.Tests.Logging;
using Xunit;
using Xunit.Abstractions;

namespace BTCPayServer.Tests
{
    public class LanguageServiceTests
    {
        public const int TestTimeout = TestUtils.TestTimeout;
        public LanguageServiceTests(ITestOutputHelper helper)
        {
            Logs.Tester = new XUnitLog(helper) { Name = "Tests" };
            Logs.LogProvider = new XUnitLogProvider(helper);
        }

        [Fact(Timeout = TestTimeout)]
        [Trait("Integration", "Integration")]
        public async Task CanAutoDetectLanguage()
        {
            using (var tester = ServerTester.Create())
            {
                await tester.StartAsync();
                var languageService = tester.PayTester.GetService<LanguageService>();
                
                // Most common format. First option does not have a quality score. Others do in descending order.
                // Result should be nl-NL (because the default weight is 1 for nl)
                var lang1 = languageService.FindLanguageInAcceptLanguageHeader("nl,fr;q=0.7,en;q=0.5");
                Assert.NotNull(lang1);
                Assert.Equal("nl-NL", lang1?.Code);

                // Most common format. First option does not have a quality score. Others do in descending order. This time the first option includes a country.
                // Result should be nl-NL (because the default weight is 1 for nl-BE and it does not exist in BTCPay Server, but nl-NL does and applies too for language "nl")
                var lang2 = languageService.FindLanguageInAcceptLanguageHeader("nl-BE,fr;q=0.7,en;q=0.5");
                Assert.NotNull(lang2);
                Assert.Equal("nl-NL", lang2?.Code);

                // Unusual format, but still valid. All values have a quality score and not ordered.
                // Result should be fr-FR (because 0.7 is the highest quality score)
                var lang3 = languageService.FindLanguageInAcceptLanguageHeader("nl;q=0.1,fr;q=0.7,en;q=0.5");
                Assert.NotNull(lang3);
                Assert.Equal("fr-FR", lang3?.Code);

                // Unusual format, but still valid. Some language is given that we don't have and a wildcard for everything else. 
                // Result should be NULL, because "xx" does not exist and * is a wildcard and has no meaning.
                var lang4 = languageService.FindLanguageInAcceptLanguageHeader("xx,*;q=0.5");
                Assert.Null(lang4);
            }
        }
    }
}