Fix FormUrlEncodedMatcher (+ refactor values / matchers logic) (#1503)

* Fix FormUrlEncodedMatcher

* tests

* Apply suggestions from code review

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Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* fix comments

---------

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

src/WireMock.Net.Abstractions/Models/IBodyData.cs

@@ -46,7 +46,7 @@ public interface IBodyData
     /// <summary>
     /// The body as Form UrlEncoded dictionary.
     /// </summary>
-    IDictionary<string, string>? BodyAsFormUrlEncoded { get; set; }
+    IDictionary<string, WireMockList<string>>? BodyAsFormUrlEncoded { get; set; }
 
     /// <summary>
     /// The detected body type (detection based on body content).

src/WireMock.Net.Abstractions/Types/WireMockList.cs

@@ -46,6 +46,98 @@ public class WireMockList<T> : List<T>
     /// <param name="values">The values to set.</param>
     public static implicit operator WireMockList<T>(T[] values) => new(values);
 
+    /// <summary>
+    /// Operator for equality comparison from WireMockList to T
+    /// </summary>
+    public static bool operator ==(WireMockList<T>? left, T? right)
+    {
+        if (ReferenceEquals(left, right))
+        {
+            return true;
+        }
+
+        if (left?.Count == 1 && Equals(left[0], right))
+        {
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    /// Operator for equality comparison from T to WireMockList
+    /// </summary>
+    public static bool operator ==(T? left, WireMockList<T>? right)
+    {
+        if (ReferenceEquals(left, right))
+        {
+            return true;
+        }
+
+        if (right?.Count == 1 && Equals(left, right[0]))
+        {
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    /// Operator for inequality comparison from WireMockList to T
+    /// </summary>
+    public static bool operator !=(WireMockList<T>? left, T? right) => !(left == right);
+
+    /// <summary>
+    /// Operator for inequality comparison from T to WireMockList
+    /// </summary>
+    public static bool operator !=(T? left, WireMockList<T>? right) => !(left == right);
+
+    /// <summary>
+    /// Determines whether the specified object is equal to the current instance.
+    /// Two <see cref="WireMockList{T}"/> instances are equal if they contain the same elements in the same order.
+    /// </summary>
+    public override bool Equals(object? obj)
+    {
+        if (ReferenceEquals(this, obj))
+        {
+            return true;
+        }
+
+        if (obj is WireMockList<T> other)
+        {
+            if (Count != other.Count)
+            {
+                return false;
+            }
+
+            for (var i = 0; i < Count; i++)
+            {
+                if (!Equals(this[i], other[i]))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    /// Returns a hash code for this instance based on its elements.
+    /// </summary>
+    public override int GetHashCode()
+    {
+        var hashCode = 17;
+        foreach (var item in this)
+        {
+            hashCode = hashCode * 31 + (item?.GetHashCode() ?? 0);
+        }
+
+        return hashCode;
+    }
+
     /// <summary>
     /// Returns a <see cref="string" /> that represents this instance.
     /// </summary>
@@ -61,7 +153,7 @@ public class WireMockList<T> : List<T>
                 {
                     return strValue;
                 }
-               
+
                 return this[0]?.ToString() ?? string.Empty;
 
             default: