Add public API verification test.

Fixes #72

.gitignore

@@ -287,3 +287,4 @@ __pycache__/
 *.odx.cs
 *.xsd.cs
 /binaries
+/**/ApiApprovals.CompressionPlugin.received.txt

src/ServiceBus.AttachmentPlugin.Tests/ApiApprovals.cs

@@ -0,0 +1,18 @@
+namespace ServiceBus.AttachmentPlugin.Tests
+{
+    using PublicApiGenerator;
+    using Xunit;
+
+    public class ApiApprovals
+    {
+        [Fact]
+        public void CompressionPlugin()
+        {
+            var publicApi = ApiGenerator.GeneratePublicApi(typeof(AzureStorageAttachment).Assembly,
+                whitelistedNamespacePrefixes: new[] { "Microsoft.Azure.ServiceBus." },
+                excludeAttributes: new[] { "System.Runtime.Versioning.TargetFrameworkAttribute" });
+
+            Approver.Verify(publicApi);
+        }
+    }
+}

src/ServiceBus.AttachmentPlugin.Tests/ApprovalFiles/ApiApprovals.CompressionPlugin.approved.txt

@@ -0,0 +1,27 @@
+[assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ServiceBus.AttachmentPlugin.Tests")]
+namespace Microsoft.Azure.ServiceBus
+{
+    public class AzureStorageAttachmentConfiguration
+    {
+        public AzureStorageAttachmentConfiguration(string connectionString, string containerName = "attachments", string messagePropertyToIdentifyAttachmentBlob = "$attachment.blob", System.Func<Microsoft.Azure.ServiceBus.Message, bool> messageMaxSizeReachedCriteria = null) { }
+        public AzureStorageAttachmentConfiguration(Microsoft.Azure.ServiceBus.IProvideStorageConnectionString connectionStringProvider, string containerName = "attachments", string messagePropertyToIdentifyAttachmentBlob = "$attachment.blob", System.Func<Microsoft.Azure.ServiceBus.Message, bool> messageMaxSizeReachedCriteria = null) { }
+    }
+    public class static AzureStorageAttachmentConfigurationExtensions
+    {
+        public static Microsoft.Azure.ServiceBus.AzureStorageAttachmentConfiguration WithSasUri(this Microsoft.Azure.ServiceBus.AzureStorageAttachmentConfiguration azureStorageAttachmentConfiguration, string messagePropertyToIdentifySasUri = "$attachment.sas.uri", System.Nullable<System.TimeSpan> sasTokenValidationTime = null) { }
+    }
+    public class static AzureStorageAttachmentExtensions
+    {
+        public static Microsoft.Azure.ServiceBus.Core.ServiceBusPlugin RegisterAzureStorageAttachmentPlugin(this Microsoft.Azure.ServiceBus.ClientEntity client, Microsoft.Azure.ServiceBus.AzureStorageAttachmentConfiguration configuration) { }
+        public static Microsoft.Azure.ServiceBus.Core.ServiceBusPlugin RegisterAzureStorageAttachmentPluginForReceivingOnly(this Microsoft.Azure.ServiceBus.ClientEntity client, string messagePropertyToIdentifySasUri = "$attachment.sas.uri") { }
+    }
+    public interface IProvideStorageConnectionString
+    {
+        System.Threading.Tasks.Task<string> GetConnectionString();
+    }
+    public class PlainTextConnectionStringProvider : Microsoft.Azure.ServiceBus.IProvideStorageConnectionString
+    {
+        public PlainTextConnectionStringProvider(string connectionString) { }
+        public System.Threading.Tasks.Task<string> GetConnectionString() { }
+    }
+}

src/ServiceBus.AttachmentPlugin.Tests/ApprovalFiles/Approver.cs

@@ -0,0 +1,89 @@
+// Adopted from https://github.com/Particular/Particular.Approvals/blob/master/src/Particular.Approvals/Approver.cs
+
+namespace Xunit
+{
+    using System;
+    using System.Diagnostics;
+    using System.IO;
+    using System.Reflection;
+    using Newtonsoft.Json;
+    using Newtonsoft.Json.Converters;
+
+    /// <summary>
+    /// Verifies that values contain approved content.
+    /// </summary>
+    static class Approver
+    {
+        static string TestDirectory
+        {
+            get
+            {
+                var codeBaseUrl = new Uri(Assembly.GetExecutingAssembly().CodeBase);
+                var codeBasePath = Uri.UnescapeDataString(codeBaseUrl.AbsolutePath);
+                var dirPath = Path.GetDirectoryName(codeBasePath);
+                return Path.Combine(dirPath, "..", "..", "..", "ApprovalFiles");
+            }
+        }
+
+        static readonly string approvalFilesPath = TestDirectory;
+        static readonly JsonSerializerSettings jsonSerializerSettings;
+
+        static Approver()
+        {
+            jsonSerializerSettings = new JsonSerializerSettings
+            {
+                Formatting = Formatting.Indented
+            };
+
+            jsonSerializerSettings.Converters.Add(new StringEnumConverter());
+        }
+
+        /// <summary>
+        /// Verifies that the received string matches the contents of the corresponding approval file.
+        /// </summary>
+        /// <param name="value">The string to verify.</param>
+        /// <param name="scrubber">A delegate that modifies the received string before comparing it to the approval file.</param>
+        /// <param name="scenario">A value that will be added to the name of the approval file.</param>
+        public static void Verify(string value, Func<string, string> scrubber = null, string scenario = null)
+        {
+            var st = new StackTrace();
+            var sf = st.GetFrame(1);
+            var currentMethodName = sf.GetMethod();
+
+            var className = currentMethodName.DeclaringType.Name;
+            var methodName = currentMethodName.Name;
+            var scenarioName = string.IsNullOrEmpty(scenario) ? "" : scenario + ".";
+
+            if (scrubber != null)
+            {
+                value = scrubber(value);
+            }
+
+            var receivedFile = Path.Combine(approvalFilesPath, $"{className}.{methodName}.{scenarioName}received.txt");
+            File.WriteAllText(receivedFile, value);
+
+            var approvedFile = Path.Combine(approvalFilesPath, $"{className}.{methodName}.{scenarioName}approved.txt");
+            var approvedText = File.ReadAllText(approvedFile);
+
+            var normalizedApprovedText = approvedText.Replace("\r\n", "\n");
+            var normalizedReceivedText = value.Replace("\r\n", "\n");
+
+            Assert.Equal(normalizedApprovedText, normalizedReceivedText);
+
+            File.Delete(receivedFile);
+        }
+
+        /// <summary>
+        /// Verifies that the received object, after it has been serialized, matches the contents of the corresponding approval file.
+        /// </summary>
+        /// <param name="value">The object to verify.</param>
+        /// <param name="scrubber">A delegate that modifies the received object, after it has been serialized, before comparing it to the approval file.</param>
+        /// <param name="scenario">A value that will be added to the name of the approval file.</param>
+        public static void Verify(object value, Func<string, string> scrubber = null, string scenario = null)
+        {
+            var json = JsonConvert.SerializeObject(value, jsonSerializerSettings);
+
+            Verify(json, scrubber, scenario);
+        }
+    }
+}

src/ServiceBus.AttachmentPlugin.Tests/ServiceBus.AttachmentPlugin.Tests.csproj

@@ -2,6 +2,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netcoreapp2.1;net461</TargetFrameworks>
+    <RootNamespace>ServiceBus.AttachmentPlugin.Tests</RootNamespace>
+    <Optimize>false</Optimize>
   </PropertyGroup>
 
   <ItemGroup>
@@ -15,4 +17,14 @@
     <ProjectReference Include="..\ServiceBus.AttachmentPlugin\ServiceBus.AttachmentPlugin.csproj" />
   </ItemGroup>
 
+  <ItemGroup Label="API Approvals">
+    <PackageReference Include="PublicApiGenerator" Version="8.0.1" />
+    <PackageReference Include="Newtonsoft.Json" Version="[12.0.1, 13.0.0)" />
+    <None Remove="ApprovalFiles\ApiApprovals.CompressionPlugin.received.txt" />
+  </ItemGroup>
+
+  <ItemGroup Label="Force the latest of the transitive dependency">
+    <PackageReference Include="Microsoft.Azure.ServiceBus" Version="3.2.1" />
+  </ItemGroup>
+
 </Project>

src/ServiceBus.AttachmentPlugin.Tests/When_registering_plugin.cs

@@ -54,7 +54,9 @@ public override void UnregisterPlugin(string serviceBusPluginName)
                 RegisteredPlugins.Remove(toRemove);
             }
 
+            public override string Path { get; }
             public override TimeSpan OperationTimeout { get; set; }
+            public override ServiceBusConnection ServiceBusConnection { get; }
             public override IList<ServiceBusPlugin> RegisteredPlugins { get; }
 
             protected override Task OnClosingAsync()

src/ServiceBus.AttachmentPlugin.Tests/When_reusing_plugin.cs

@@ -63,7 +63,9 @@ public override void UnregisterPlugin(string serviceBusPluginName)
                 RegisteredPlugins.Remove(toRemove);
             }
 
+            public override string Path { get; }
             public override TimeSpan OperationTimeout { get; set; }
+            public override ServiceBusConnection ServiceBusConnection { get; }
             public override IList<ServiceBusPlugin> RegisteredPlugins { get; }
 
             protected override Task OnClosingAsync()