Check if the path is valid when using WithPath(...) (#1377)

src/WireMock.Net.Abstractions/Admin/Mappings/MatcherModel.cs

@@ -22,7 +22,7 @@ public class MatcherModel
     public object? Pattern { get; set; }
 
     /// <summary>
-    /// Gets or sets the patterns. Can be array of strings (default) or an array of objects.
+    /// Gets or sets the patterns. Can be an array of strings (default) or an array of objects.
     /// </summary>
     public object[]? Patterns { get; set; }
 

src/WireMock.Net.Abstractions/BuilderExtensions/RequestModelBuilder.cs

@@ -1,6 +1,7 @@
 // Copyright © WireMock.Net
 
 using System;
+using WireMock.Validators;
 
 // ReSharper disable once CheckNamespace
 namespace WireMock.Admin.Mappings;
@@ -94,9 +95,14 @@ public partial class RequestModelBuilder
     }
 
     /// <summary>
-    /// Set the Path.
+    /// Set the Path. Must start with a forward slash (/).
     /// </summary>
-    public RequestModelBuilder WithPath(string value) => WithPath(() => value);
+    public RequestModelBuilder WithPath(string value)
+    {
+        PathValidator.ValidateAndThrow(value);
+
+        return WithPath(() => value);
+    }
 
     /// <summary>
     /// Set the Path.

src/WireMock.Net.Abstractions/Validators/PathValidator.cs

@@ -0,0 +1,19 @@
+// Copyright © WireMock.Net
+
+using System;
+
+namespace WireMock.Validators;
+
+public static class PathValidator
+{
+    /// <summary>
+    /// A valid path must start with a '/' and cannot be null, empty or whitespace.
+    /// </summary>
+    public static void ValidateAndThrow(string? path, string? paramName = null)
+    {
+        if (string.IsNullOrWhiteSpace(path) || path?.StartsWith("/") == false)
+        {
+            throw new ArgumentException("Path must start with a '/' and cannot be null, empty or whitespace.", paramName ?? nameof(path));
+        }
+    }
+}

src/WireMock.Net.Minimal/RequestBuilders/Request.WithPath.cs

@@ -4,6 +4,7 @@ using System;
 using Stef.Validation;
 using WireMock.Matchers;
 using WireMock.Matchers.Request;
+using WireMock.Validators;
 
 namespace WireMock.RequestBuilders;
 
@@ -34,6 +35,10 @@ public partial class Request
     public IRequestBuilder WithPath(MatchOperator matchOperator, params string[] paths)
     {
         Guard.NotNullOrEmpty(paths);
+        foreach (var path in paths)
+        {
+            PathValidator.ValidateAndThrow(path, nameof(paths));
+        }
 
         _requestMatchers.Add(new RequestMessagePathMatcher(MatchBehaviour.AcceptOnMatch, matchOperator, paths));
         return this;