Make WireMockAssertions extendable (#1082)

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

@@ -0,0 +1,33 @@
+#pragma warning disable CS1591
+using System;
+
+// ReSharper disable once CheckNamespace
+namespace WireMock.FluentAssertions;
+
+public partial class WireMockAssertions
+{
+    [CustomAssertion]
+    public AndWhichConstraint<WireMockAssertions, string> FromClientIP(string clientIP, string because = "", params object[] becauseArgs)
+    {
+        var (filter, condition) = BuildFilterAndCondition(request => string.Equals(request.ClientIP, clientIP, StringComparison.OrdinalIgnoreCase));
+
+        Execute.Assertion
+            .BecauseOf(because, becauseArgs)
+            .Given(() => RequestMessages)
+            .ForCondition(requests => CallsCount == 0 || requests.Any())
+            .FailWith(
+                "Expected {context:wiremockserver} to have been called from client IP {0}{reason}, but no calls were made.",
+                clientIP
+            )
+            .Then
+            .ForCondition(condition)
+            .FailWith(
+                "Expected {context:wiremockserver} to have been called from client IP {0}{reason}, but didn't find it among the calls from IP(s) {1}.",
+                _ => clientIP, requests => requests.Select(request => request.ClientIP)
+            );
+
+        FilterRequestMessages(filter);
+
+        return new AndWhichConstraint<WireMockAssertions, string>(this, clientIP);
+    }
+}