Dynamic response handlebars templating (2) (#273)

* Dynamic response files using Handlebars templating
(#270)

* * Response templating / transformation using Handlebars and extensions

* Add unit test for JsonPath and BodyAsFile mapping (#272)

* fix merge issue

test/WireMock.Net.Tests/ResponseBuilders/ResponseWithHandlebarsTests.cs

@@ -231,5 +231,32 @@ public async Task Response_ProvideResponse_Handlebars_WithBodyAsFile()
             // Assert
             Check.That(responseMessage.BodyData.BodyAsFile).Equals(@"c:\1\test.xml");
         }
+
+        [Fact]
+        public async Task Response_ProvideResponse_Handlebars_WithBodyAsFile_JsonPath()
+        {
+            // Assign
+            string jsonString = "{ \"MyUniqueNumber\": \"1\" }";
+            var bodyData = new BodyData
+            {
+                BodyAsString = jsonString,
+                BodyAsJson = JsonConvert.DeserializeObject(jsonString),
+                DetectedBodyType = BodyType.Json,
+                DetectedBodyTypeFromContentType = BodyType.Json,
+                Encoding = Encoding.UTF8
+            };
+            var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "POST", ClientIp, bodyData);
+
+            string jsonPath = "\"$.MyUniqueNumber\"";
+            var response = Response.Create()
+                .WithTransformer()
+                .WithBodyFromFile(@"c:\\{{JsonPath.SelectToken request.body " + jsonPath + "}}\\test.json"); // why use a \\ here ?
+
+            // Act
+            var responseMessage = await response.ProvideResponseAsync(request);
+
+            // Assert
+            Check.That(responseMessage.BodyData.BodyAsFile).Equals(@"c:\1\test.json");
+        }
     }
 }