Fix FluentAssertions (actual body is not displayed in error message)

Author: StefH

src/WireMock.Net.FluentAssertions/Assertions/WireMockAssertions.WithBody.cs

@@ -1,6 +1,8 @@
 #pragma warning disable CS1591
 using System;
 using System.Collections.Generic;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
 using WireMock.Matchers;
 
 // ReSharper disable once CheckNamespace
@@ -9,7 +11,7 @@ namespace WireMock.FluentAssertions;
 public partial class WireMockAssertions
 {
     private const string MessageFormatNoCalls = "Expected {context:wiremockserver} to have been called using body {0}{reason}, but no calls were made.";
-    private const string MessageFormat = "Expected {context:wiremockserver} to have been called using body {0}{reason}, but didn't find it among the body {1}.";
+    private const string MessageFormat = "Expected {context:wiremockserver} to have been called using body {0}{reason}, but didn't find it among the body/bodies {1}.";
 
     [CustomAssertion]
     public AndConstraint<WireMockAssertions> WithBody(string body, string because = "", params object[] becauseArgs)
@@ -104,14 +106,14 @@ private AndConstraint<WireMockAssertions> ExecuteAssertionWithBodyAsIObjectMatch
             .ForCondition(requests => CallsCount == 0 || requests.Any())
             .FailWith(
                 MessageFormatNoCalls,
-                matcher.Value
+                FormatBody(matcher.Value)
             )
             .Then
             .ForCondition(condition)
             .FailWith(
                 MessageFormat,
-                _ => matcher.Value,
-                requests => requests.Select(expression)
+                _ => FormatBody(matcher.Value),
+                requests => FormatBodies(requests.Select(expression))
             );
 
         FilterRequestMessages(filter);
@@ -148,4 +150,20 @@ private AndConstraint<WireMockAssertions> ExecuteAssertionWithBodyAsBytesExactOb
 
         return new AndConstraint<WireMockAssertions>(this);
     }
+
+    private static string? FormatBody(object? body)
+    {
+        return body switch
+        {
+            null => null,
+            JObject jObject => jObject.ToString(Formatting.None),
+            JToken jToken => jToken.ToString(Formatting.None),
+            _ => JToken.FromObject(body).ToString(Formatting.None)
+        };
+    }
+
+    private static string? FormatBodies(IEnumerable<object?> bodies)
+    {
+        return string.Join(", ", bodies.Select(FormatBody));
+    }
 }

test/WireMock.Net.Tests/FluentAssertions/WireMockAssertionsTests.cs

@@ -702,7 +702,11 @@ public async Task HaveReceived1Call_WithBodyAsJson()
         // Act
         var httpClient = new HttpClient();
 
-        await httpClient.PostAsync($"{server.Url}/a", new StringContent(@"{ ""x"": ""y"" }"));
+        var requestBody = new
+        {
+            x = "y"
+        };
+        await httpClient.PostAsJsonAsync($"{server.Url}/a", requestBody);
 
         // Assert
         server
@@ -740,6 +744,41 @@ public async Task HaveReceived1Call_WithBodyAsJson()
         server.Stop();
     }
 
+    [Fact]
+    public async Task WithBodyAsJson_When_NoMatch_ShouldHaveCorrectErrorMessage()
+    {
+        // Arrange
+        var server = WireMockServer.Start();
+
+        server
+            .Given(Request.Create().WithPath("/a").UsingPost().WithBodyAsJson(new { x = "y" }))
+            .RespondWith(Response.Create().WithBody("A response"));
+
+        // Act
+        var httpClient = new HttpClient();
+
+        var requestBody = new
+        {
+            x = "123"
+        };
+        await httpClient.PostAsJsonAsync($"{server.Url}/a", requestBody);
+
+        // Assert
+        Action act = () => server
+            .Should()
+            .HaveReceived(1)
+            .Calls()
+            .WithBodyAsJson(new { x = "y" })
+            .And
+            .UsingPost();
+
+        act.Should()
+            .Throw<Exception>()
+            .WithMessage("Expected wiremockserver to have been called using body \"{\"x\":\"y\"}\", but didn't find it among the body/bodies \"{\"x\":\"123\"}\".");
+
+        server.Stop();
+    }
+
     [Fact]
     public async Task HaveReceived1Call_WithBodyAsBytes()
     {