feat: Registry (#21)

fixes #18

Signed-off-by: Samson Amaugo <sammychinedu2ky@gmail.com>

Oras.Tests/Oras.Tests.csproj

@@ -10,6 +10,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0-preview-20230223-05" />
+    <PackageReference Include="Moq" Version="4.18.4" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

Oras.Tests/RemoteTest/RegistryTest.cs

@@ -0,0 +1,150 @@
+using Moq;
+using Moq.Protected;
+using Oras.Remote;
+using System.Net;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+using Xunit;
+
+namespace Oras.Tests.RemoteTest
+{
+    public class RegistryTest
+    {
+
+        public static HttpClient CustomClient(Func<HttpRequestMessage, CancellationToken, HttpResponseMessage> func)
+        {
+            var moqHandler = new Mock<DelegatingHandler>();
+            moqHandler.Protected().Setup<Task<HttpResponseMessage>>(
+                "SendAsync",
+                ItExpr.IsAny<HttpRequestMessage>(),
+                ItExpr.IsAny<CancellationToken>()
+            ).ReturnsAsync(func);
+            return new HttpClient(moqHandler.Object);
+        }
+
+        /// <summary>
+        /// TestRegistry_PingAsync tests the PingAsync method of the Registry class.
+        /// </summary>
+        /// <returns></returns>
+        [Fact]
+        public async Task TestRegistry_PingAsync()
+        {
+            var V2Implemented = true;
+            var func = (HttpRequestMessage req, CancellationToken cancellationToken) =>
+            {
+                var res = new HttpResponseMessage();
+                res.RequestMessage = req;
+
+                if (req.Method != HttpMethod.Get && req.RequestUri.AbsolutePath == $"/v2/")
+                {
+                    res.StatusCode = HttpStatusCode.NotFound;
+                    return res;
+                }
+
+                if (V2Implemented)
+                {
+                    res.StatusCode = HttpStatusCode.OK;
+                    return res;
+                }
+                else
+                {
+                    res.StatusCode = HttpStatusCode.NotFound;
+                    return res;
+                }
+            };
+            var registry = new Oras.Remote.Registry("localhost:5000");
+            registry.PlainHTTP = true;
+            registry.HttpClient = CustomClient(func);
+            var cancellationToken = new CancellationToken();
+            await registry.PingAsync(cancellationToken);
+            V2Implemented = false;
+            await Assert.ThrowsAnyAsync<Exception>(
+                async () => await registry.PingAsync(cancellationToken));
+        }
+
+        /// <summary>
+        /// TestRegistry_Repositories tests the ListRepositoriesAsync method of the Registry class.
+        /// </summary>
+        /// <returns></returns>
+        /// <exception cref="Exception"></exception>
+        [Fact]
+        public async Task TestRegistry_Repositories()
+        {
+            var repoSet = new List<List<string>>()
+            {
+                new() {"the", "quick", "brown", "fox"},
+                new() {"jumps", "over", "the", "lazy"},
+                new() {"dog"}
+            };
+            var func = (HttpRequestMessage req, CancellationToken cancellationToken) =>
+            {
+                var res = new HttpResponseMessage();
+                res.RequestMessage = req;
+                if (req.Method != HttpMethod.Get ||
+                    req.RequestUri.AbsolutePath != "/v2/_catalog"
+                   )
+                {
+                    return new HttpResponseMessage(HttpStatusCode.NotFound);
+                }
+
+                var q = req.RequestUri.Query;
+                try
+                {
+                    var n = int.Parse(Regex.Match(q, @"(?<=n=)\d+").Value);
+                    if (n != 4) throw new Exception();
+                }
+                catch (Exception e)
+                {
+                    return new HttpResponseMessage(HttpStatusCode.BadRequest);
+                }
+
+                var repos = new List<string>();
+                var serverUrl = "http://localhost:5000";
+                var matched = Regex.Match(q, @"(?<=test=)\w+").Value;
+                switch (matched)
+                {
+                    case "foo":
+                        repos = repoSet[1];
+                        res.Headers.Add("Link", $"<{serverUrl}/v2/_catalog?n=4&test=bar>; rel=\"next\"");
+                        break;
+                    case "bar":
+                        repos = repoSet[2];
+                        break;
+                    default:
+                        repos = repoSet[0];
+                        res.Headers.Add("Link", $"</v2/_catalog?n=4&test=foo>; rel=\"next\"");
+                        break;
+                }
+
+                var repositoryList = new ResponseTypes.RepositoryList
+                {
+                    Repositories = repos.ToArray()
+                };
+                res.Content = new StringContent(JsonSerializer.Serialize(repositoryList));
+                return res;
+
+            };
+
+            var registry = new Oras.Remote.Registry("localhost:5000");
+            registry.PlainHTTP = true;
+            registry.HttpClient = CustomClient(func);
+            var cancellationToken = new CancellationToken();
+            registry.TagListPageSize = 4;
+
+
+
+            var index = 0;
+            await registry.Repositories("", async (string[] got) =>
+            {
+                if (index > 2)
+                {
+                    throw new Exception($"Error out of range: {index}");
+                }
+
+                var repos = repoSet[index];
+                index++;
+                Assert.Equal(got, repos);
+            }, cancellationToken);
+        }
+    }
+}