Simplify the ApiApproval test (#2381)

* Simplify the ApiApproval test (1/2)

Simplify how paths relative to the solution directory are accessed.

* Simplify the ApiApproval test (2/2)

Actually use the Verify.DiffPlex integration instead of using DiffPlex directly.

* Address pull request feedback

* Use the new minimal diff output style

Tests/Approval.Tests/ApiApproval.cs

@@ -1,16 +1,13 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
+using System.IO;
+using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
-using System.Text;
 using System.Threading.Tasks;
 using System.Xml.Linq;
 using System.Xml.XPath;
-using DiffPlex.DiffBuilder;
-using DiffPlex.DiffBuilder.Model;
 using PublicApiGenerator;
 using VerifyTests;
+using VerifyTests.DiffPlex;
 using VerifyXunit;
 using Xunit;
 
@@ -19,72 +16,30 @@ namespace Approval.Tests;
 [UsesVerify]
 public class ApiApproval
 {
+    static ApiApproval() => VerifyDiffPlex.Initialize(OutputType.Minimal);
+
     [Theory]
     [ClassData(typeof(TargetFrameworksTheoryData))]
-    public Task ApproveApi(string frameworkVersion)
+    public Task ApproveApi(string framework)
     {
-        string codeBase = Assembly.GetExecutingAssembly().Location;
-        var uri = new UriBuilder(new Uri(codeBase));
-        string assemblyPath = Uri.UnescapeDataString(uri.Path);
-        var containingDirectory = Path.GetDirectoryName(assemblyPath);
-        var configurationName = new DirectoryInfo(containingDirectory).Parent.Name;
-
-        var assemblyFile = Path.GetFullPath(
-            Path.Combine(
-                GetSourceDirectory(),
-                Path.Combine("..", "..", "Src", "FluentAssertions", "bin", configurationName, frameworkVersion,
-                    "FluentAssertions.dll")));
-
-        var assembly = Assembly.LoadFile(Path.GetFullPath(assemblyFile));
+        var configuration = typeof(ApiApproval).Assembly.GetCustomAttribute<AssemblyConfigurationAttribute>()!.Configuration;
+        var assemblyFile = CombinedPaths("Src", "FluentAssertions", "bin", configuration, framework, "FluentAssertions.dll");
+        var assembly = Assembly.LoadFile(assemblyFile);
         var publicApi = assembly.GeneratePublicApi(options: null);
 
         return Verifier
             .Verify(publicApi)
             .ScrubLinesContaining("FrameworkDisplayName")
             .UseDirectory(Path.Combine("ApprovedApi", "FluentAssertions"))
-            .UseStringComparer(OnlyIncludeChanges)
-            .UseFileName(frameworkVersion)
+            .UseFileName(framework)
             .DisableDiff();
     }
 
-    private static string GetSourceDirectory([CallerFilePath] string path = "") => Path.GetDirectoryName(path);
-
-    // Copied from https://github.com/VerifyTests/Verify.DiffPlex/blob/master/src/Verify.DiffPlex/VerifyDiffPlex.cs
-    public static Task<CompareResult> OnlyIncludeChanges(string received, string verified, IReadOnlyDictionary<string, object> _)
-    {
-        var diff = InlineDiffBuilder.Diff(verified, received);
-
-        var builder = new StringBuilder();
-
-        foreach (var line in diff.Lines)
-        {
-            switch (line.Type)
-            {
-                case ChangeType.Inserted:
-                    builder.Append("+ ");
-                    break;
-                case ChangeType.Deleted:
-                    builder.Append("- ");
-                    break;
-                default:
-                    // omit unchanged files
-                    continue;
-            }
-
-            builder.AppendLine(line.Text);
-        }
-
-        var compareResult = CompareResult.NotEqual(builder.ToString());
-        return Task.FromResult(compareResult);
-    }
-
     private class TargetFrameworksTheoryData : TheoryData<string>
     {
         public TargetFrameworksTheoryData()
         {
-            var csproj = Path.Combine(GetSourceDirectory(),
-                Path.Combine("..", "..", "Src", "FluentAssertions", "FluentAssertions.csproj"));
-
+            var csproj = CombinedPaths("Src", "FluentAssertions", "FluentAssertions.csproj");
             var project = XDocument.Load(csproj);
             var targetFrameworks = project.XPathSelectElement("/Project/PropertyGroup/TargetFrameworks");
 
@@ -94,4 +49,10 @@ public TargetFrameworksTheoryData()
             }
         }
     }
+
+    private static string GetSolutionDirectory([CallerFilePath] string path = "") =>
+        Path.Combine(Path.GetDirectoryName(path)!, "..", "..");
+
+    private static string CombinedPaths(params string[] paths) =>
+        Path.GetFullPath(Path.Combine(paths.Prepend(GetSolutionDirectory()).ToArray()));
 }

Tests/Approval.Tests/Approval.Tests.csproj

@@ -12,7 +12,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="PublicApiGenerator" Version="11.0.0" />
-    <PackageReference Include="Verify.DiffPlex" Version="2.2.1" />
+    <PackageReference Include="Verify.DiffPlex" Version="2.3.0" />
     <PackageReference Include="Verify.Xunit" Version="22.1.4" />
   </ItemGroup>