Add unit test for custom port handling

Add a unit test to verify custom handling of ports and schemes works as intended.

tests/HttpClientInterception.Tests/HttpRequestInterceptionBuilderTests.cs

@@ -1067,6 +1067,54 @@ public static async Task Using_The_Same_Builder_For_Multiple_Registrations_On_Th
             await HttpAssert.GetAsync(options, "https://api.github.com:443/orgs/justeat");
         }
 
+        [Fact]
+        public static async Task Using_The_Same_Builder_For_Multiple_Registrations_With_Custom_Ports()
+        {
+            // Arrange
+            var options = new HttpClientInterceptorOptions()
+            {
+                ThrowOnMissingRegistration = true
+            };
+
+            var builder = new HttpRequestInterceptionBuilder()
+                .ForPort(123)
+                .ForHttps()
+                .ForHost("api.github.com")
+                .ForPath("orgs/justeat")
+                .RegisterWith(options);
+
+            // Change to a different scheme without changing the port
+            builder = builder
+                .ForHttp()
+                .RegisterWith(options);
+
+            // Change the port and not the scheme
+            builder = builder
+                .ForPort(456)
+                .RegisterWith(options);
+
+            // Change the scheme and use an explicit port
+            builder = builder
+                .ForHttps()
+                .ForPort(443)
+                .RegisterWith(options);
+
+            // Restore default scheme and port
+            builder = builder
+                .ForHttp()
+                .ForPort(-1)
+                .RegisterWith(options);
+
+            // Act and Assert
+            await HttpAssert.GetAsync(options, "https://api.github.com:123/orgs/justeat");
+            await HttpAssert.GetAsync(options, "http://api.github.com:123/orgs/justeat");
+            await HttpAssert.GetAsync(options, "http://api.github.com:456/orgs/justeat");
+            await HttpAssert.GetAsync(options, "https://api.github.com/orgs/justeat");
+            await HttpAssert.GetAsync(options, "https://api.github.com:443/orgs/justeat");
+            await HttpAssert.GetAsync(options, "http://api.github.com/orgs/justeat");
+            await HttpAssert.GetAsync(options, "http://api.github.com:80/orgs/justeat");
+        }
+
         private sealed class CustomObject
         {
             internal enum Color