Add unit tests

NullSharp.sln

@@ -5,6 +5,8 @@ VisualStudioVersion = 15.0.26124.0
 MinimumVisualStudioVersion = 15.0.26124.0
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NullSharp", "NullSharp\NullSharp.csproj", "{573D3111-7187-42BE-912E-4147706E8829}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NullSharpTests", "NullSharpTests\NullSharpTests.csproj", "{3121E38F-B6F7-4641-9799-162EA6C8607D}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -30,5 +32,17 @@ Global
 		{573D3111-7187-42BE-912E-4147706E8829}.Release|x64.Build.0 = Release|Any CPU
 		{573D3111-7187-42BE-912E-4147706E8829}.Release|x86.ActiveCfg = Release|Any CPU
 		{573D3111-7187-42BE-912E-4147706E8829}.Release|x86.Build.0 = Release|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Debug|x64.Build.0 = Debug|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Debug|x86.Build.0 = Debug|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Release|x64.ActiveCfg = Release|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Release|x64.Build.0 = Release|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Release|x86.ActiveCfg = Release|Any CPU
+		{3121E38F-B6F7-4641-9799-162EA6C8607D}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

NullSharp/NullStream.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using System.IO;
 using System.Net.Http;
 using System.Threading;
@@ -9,7 +10,7 @@ namespace NullSharp
     public class NullStream : Stream
     {
         public const string DefaultEndpoint = "https://devnull-as-a-service.com/dev/null";
-        private readonly HttpClient Client;
+        protected HttpClient Client { get; set; }
 
         public NullStream() : this(DefaultEndpoint) { }
 
@@ -51,6 +52,9 @@ namespace NullSharp
         public override void Write(byte[] buffer, int offset, int count) => this.WriteAsync(buffer, offset, count).Wait();
 
         public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-            => this.Client.PostAsync("", new ByteArrayContent(buffer), cancellationToken);
+            => this.Client.PostAsync(
+                "",
+                new ByteArrayContent(buffer.Skip(offset).Take(count).ToArray()),
+                cancellationToken);
     }
 }

NullSharpTests/NullSharpTests.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp2.2</TargetFramework>
+
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
+    <PackageReference Include="xunit" Version="2.4.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\NullSharp\NullSharp.csproj" />
+  </ItemGroup>
+
+</Project>

NullSharpTests/NullStreamTests.cs

@@ -0,0 +1,77 @@
+using System;
+using System.IO;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Xunit;
+using NullSharp;
+
+namespace NullSharpTests {
+    class MockableNullStream : NullStream {
+        public MockableNullStream() : base() { }
+        public MockableNullStream(string endpoint) : base(endpoint) { }
+
+        public HttpClient GetClient() => this.Client;
+        public void SetClient(HttpClient value) => this.Client = value;
+    }
+
+    class MockHttpClient : HttpClient {
+        public HttpRequestMessage LastMessage;
+        public override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) {
+            LastMessage = request;
+            return new Task<HttpResponseMessage>(() => new HttpResponseMessage());
+        }
+    }
+
+    public class NullStreamTests {
+        private MockableNullStream stream = new MockableNullStream();
+
+        [Fact]
+        public void DefaultEndpointTest() {
+            Assert.Equal("https://devnull-as-a-service.com/dev/null", stream.GetClient().BaseAddress.ToString());
+            Assert.Single(stream.GetClient().DefaultRequestHeaders.UserAgent);
+            Assert.Equal("NullSharp", stream.GetClient().DefaultRequestHeaders.UserAgent.ToString());
+        }
+
+        [Fact]
+        public void CustomEndpointTest() {
+            var customStream = new MockableNullStream("https://somewhere");
+            Assert.Equal("https://somewhere", customStream.GetClient().BaseAddress.ToString());
+        }
+
+        [Fact]
+        public void PropertiesTest() {
+            Assert.True(stream.CanWrite, "NullStream should be writable");
+            Assert.False(stream.CanRead, "NullStream should not be readable");
+            Assert.False(stream.CanSeek, "NullStream should not be seekable");
+            Assert.True(stream.CanTimeout, "NullStream should be able to time out");
+        }
+
+        [Fact]
+        public void TimeoutTest() {
+            stream.WriteTimeout = 1000000;
+            Assert.Equal(1000000, stream.WriteTimeout);
+            Assert.Equal(1000000, stream.GetClient().Timeout.TotalMilliseconds);
+        }
+
+        [Fact]
+        public void NotSupportedTest() {
+            Assert.Throws<NotSupportedException>(() => stream.Length);
+            Assert.Throws<NotSupportedException>(() => stream.SetLength(42));
+            Assert.Throws<NotSupportedException>(() => stream.Seek(0, SeekOrigin.Begin));
+            Assert.Throws<NotSupportedException>(() => stream.Position);
+            Assert.Throws<NotSupportedException>(() => stream.Position = 42);
+            Assert.Throws<NotSupportedException>(() => stream.Read(new byte[] {}, 0, 10));
+        }
+
+        [Fact]
+        public void WriteTest() {
+            stream.SetClient(new MockHttpClient() { BaseAddress = new Uri(NullStream.DefaultEndpoint) });
+            var data = new byte[] {13, 37};
+            stream.Write(data, 1, 1);
+            var request = ((MockHttpClient)stream.GetClient()).LastMessage;
+            Assert.Equal("https://devnull-as-a-service.com/dev/null", request.RequestUri.ToString());
+            Assert.IsType<ByteArrayContent>(request.Content);
+            Assert.Equal(new ByteArrayContent(new byte[] {37}), request.Content);
+        }
+    }
+}