chore: Remove redundant null check covered by JsonRequestContent (#40)

Author: hendriklhf

src/Docker.DotNet/Endpoints/SwarmOperations.cs

@@ -22,7 +22,7 @@ async Task<ServiceCreateResponse> ISwarmOperations.CreateServiceAsync(ServiceCre
     {
         if (parameters == null) throw new ArgumentNullException(nameof(parameters));
 
-        var data = new JsonRequestContent<ServiceSpec>(parameters.Service ?? throw new ArgumentNullException(nameof(parameters.Service)), DockerClient.JsonSerializer);
+        var data = new JsonRequestContent<ServiceSpec>(parameters.Service, DockerClient.JsonSerializer);
         return await _client.MakeRequestAsync<ServiceCreateResponse>(new[] { SwarmResponseHandler }, HttpMethod.Post, "services/create", null, data, RegistryAuthHeaders(parameters.RegistryAuth), cancellationToken).ConfigureAwait(false);
     }
 
@@ -33,7 +33,7 @@ async Task<SwarmUnlockResponse> ISwarmOperations.GetSwarmUnlockKeyAsync(Cancella
 
     async Task<string> ISwarmOperations.InitSwarmAsync(SwarmInitParameters parameters, CancellationToken cancellationToken)
     {
-        var data = new JsonRequestContent<SwarmInitParameters>(parameters ?? throw new ArgumentNullException(nameof(parameters)), DockerClient.JsonSerializer);
+        var data = new JsonRequestContent<SwarmInitParameters>(parameters, DockerClient.JsonSerializer);
         return await _client.MakeRequestAsync<string>(
             new ApiResponseErrorHandlingDelegate[]
             {
@@ -67,7 +67,7 @@ async Task<SwarmInspectResponse> ISwarmOperations.InspectSwarmAsync(Cancellation
 
     async Task ISwarmOperations.JoinSwarmAsync(SwarmJoinParameters parameters, CancellationToken cancellationToken)
     {
-        var data = new JsonRequestContent<SwarmJoinParameters>(parameters ?? throw new ArgumentNullException(nameof(parameters)), DockerClient.JsonSerializer);
+        var data = new JsonRequestContent<SwarmJoinParameters>(parameters, DockerClient.JsonSerializer);
         await _client.MakeRequestAsync(
             new ApiResponseErrorHandlingDelegate[]
             {
@@ -125,7 +125,7 @@ async Task ISwarmOperations.RemoveServiceAsync(string id, CancellationToken canc
 
     async Task ISwarmOperations.UnlockSwarmAsync(SwarmUnlockParameters parameters, CancellationToken cancellationToken)
     {
-        var body = new JsonRequestContent<SwarmUnlockParameters>(parameters ?? throw new ArgumentNullException(nameof(parameters)), DockerClient.JsonSerializer);
+        var body = new JsonRequestContent<SwarmUnlockParameters>(parameters, DockerClient.JsonSerializer);
         await _client.MakeRequestAsync(new[] { SwarmResponseHandler }, HttpMethod.Post, "swarm/unlock", null, body, cancellationToken).ConfigureAwait(false);
     }
 
@@ -135,7 +135,7 @@ async Task<ServiceUpdateResponse> ISwarmOperations.UpdateServiceAsync(string id,
         if (parameters == null) throw new ArgumentNullException(nameof(parameters));
 
         var query = new QueryString<ServiceUpdateParameters>(parameters);
-        var body = new JsonRequestContent<ServiceSpec>(parameters.Service ?? throw new ArgumentNullException(nameof(parameters.Service)), DockerClient.JsonSerializer);
+        var body = new JsonRequestContent<ServiceSpec>(parameters.Service, DockerClient.JsonSerializer);
         return await _client.MakeRequestAsync<ServiceUpdateResponse>(new[] { SwarmResponseHandler }, HttpMethod.Post, $"services/{id}/update", query, body, RegistryAuthHeaders(parameters.RegistryAuth), cancellationToken).ConfigureAwait(false);
     }
 
@@ -177,7 +177,7 @@ async Task<ServiceUpdateResponse> ISwarmOperations.UpdateServiceAsync(string id,
     async Task ISwarmOperations.UpdateSwarmAsync(SwarmUpdateParameters parameters, CancellationToken cancellationToken)
     {
         var query = new QueryString<SwarmUpdateParameters>(parameters ?? throw new ArgumentNullException(nameof(parameters)));
-        var body = new JsonRequestContent<Spec>(parameters.Spec ?? throw new ArgumentNullException(nameof(parameters.Spec)), DockerClient.JsonSerializer);
+        var body = new JsonRequestContent<Spec>(parameters.Spec, DockerClient.JsonSerializer);
         await _client.MakeRequestAsync(
             new ApiResponseErrorHandlingDelegate[]
             {
@@ -236,7 +236,7 @@ async Task ISwarmOperations.UpdateNodeAsync(string id, ulong version, NodeUpdate
     {
         if (string.IsNullOrEmpty(id)) throw new ArgumentNullException(nameof(id));
         var query = new EnumerableQueryString("version", new[] { version.ToString() });
-        var body = new JsonRequestContent<NodeUpdateParameters>(parameters ?? throw new ArgumentNullException(nameof(parameters)), DockerClient.JsonSerializer);
+        var body = new JsonRequestContent<NodeUpdateParameters>(parameters, DockerClient.JsonSerializer);
         await _client.MakeRequestAsync(new[] { SwarmResponseHandler }, HttpMethod.Post, $"nodes/{id}/update", query, body, cancellationToken);
     }
 }

src/Docker.DotNet/JsonRequestContent.cs

@@ -1,13 +1,14 @@
 namespace Docker.DotNet;
 
 internal class JsonRequestContent<T> : IRequestContent
+    where T : class
 {
     private readonly T _value;
     private readonly JsonSerializer _serializer;
 
     public JsonRequestContent(T val, JsonSerializer serializer)
     {
-        if (EqualityComparer<T>.Default.Equals(val))
+        if (val == null)
         {
             throw new ArgumentNullException(nameof(val));
         }

test/Docker.DotNet.Tests/JsonRequestContentTests.cs

@@ -0,0 +1,27 @@
+using System.Net.Http;
+
+namespace Docker.DotNet.Tests;
+
+public sealed class JsonRequestContentTests
+{
+    [Fact]
+    public void Constructor_ThrowsArgumentNullException_WhenValueIsNull()
+    {
+        Assert.Throws<ArgumentNullException>(() => new JsonRequestContent<object>(null, JsonSerializer.Instance));
+    }
+
+    [Fact]
+    public void Constructor_ThrowsArgumentNullException_WhenSerializerIsNull()
+    {
+        Assert.Throws<ArgumentNullException>(() => new JsonRequestContent<object>(new(), null));
+    }
+
+    [Fact]
+    public async Task GetContent_Succeeds_WhenValueAndSerializerAreValid()
+    {
+        JsonRequestContent<int[]> content = new([1], JsonSerializer.Instance);
+        using HttpContent httpContent = content.GetContent();
+        string jsonString = await httpContent.ReadAsStringAsync();
+        Assert.Equal("[1]", jsonString);
+    }
+}