Fix exception when using default logger value for BackblazeClient constructors

src/Client/Backblaze.Client.csproj

@@ -10,7 +10,7 @@
     <Authors>Microcompiler</Authors>
     <Company>Bytewizer Inc.</Company>
     <Product>Backblaze B2 Cloud Storage</Product>
-    <LangVersion>7.1</LangVersion>
+    <LangVersion>8.0</LangVersion>
     <RootNamespace>Bytewizer.Backblaze</RootNamespace>
     <VersionPrefix>1.1.0</VersionPrefix>
     <Version Condition=" '$(Version)' == '' and '$(VersionSuffix)' != '' ">$(VersionPrefix)-$(VersionSuffix)</Version>

src/Client/Client/Storage/Storage.cs

@@ -28,6 +28,8 @@ protected Storage(HttpClient client, IClientOptions options, ILoggerFactory logg
             try
             {
                 // Initialize components
+                logger ??= NullLoggerFactory.Instance;
+
                 _client = new ApiClient(client, options, logger.CreateLogger<ApiClient>(), cache);
                 _logger = logger.CreateLogger<Storage>();
             }

test/Unit/Backblaze.Tests.Unit.csproj

@@ -26,6 +26,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageReference Include="NSubstitute" Version="5.1.0" />
     <PackageReference Include="xunit" Version="2.9.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
       <PrivateAssets>all</PrivateAssets>

test/Unit/BackblazeClientTests.cs

@@ -0,0 +1,41 @@
+using System.Net.Http;
+
+using Bytewizer.Backblaze.Client;
+
+using Microsoft.Extensions.Caching.Memory;
+
+using Xunit;
+
+using NSubstitute;
+
+namespace Backblaze.Tests.Unit
+{
+	public class BackblazeClientTests
+	{
+		[Fact]
+		public void BackblazeClient_constructor_does_not_crash_on_null_loggerFactory()
+		{
+			// Arrange
+			var clientOptions = new ClientOptions();
+
+			var dummyMemoryCache = Substitute.For<IMemoryCache>();
+
+			// Act & Assert
+      new BackblazeClient(clientOptions, logger: null, dummyMemoryCache);
+		}
+
+		[Fact]
+		public void BackblazeClient_constructor_with_HttpClient_does_not_crash_on_null_loggerFactory()
+		{
+			// Arrange
+			var clientOptions = new ClientOptions();
+
+			var httpClient = new HttpClient();
+
+			var dummyMemoryCache = Substitute.For<IMemoryCache>();
+
+			// Act & Assert
+      new BackblazeClient(httpClient, clientOptions, logger: null, dummyMemoryCache);
+		}
+	}
+}