Update JSONPathMatcher.cs to cover the string path selection to a child (#993)

* Update JSONPathMatcher.cs to cover the string path selection to a child 

The .SelectToken method accept string path selection and JSONPath queries. The current code works only for the queries because the result is JObject. When the string path is selected the result is JValue and event with a valid result the code the code doesn't return valued result.
https://www.newtonsoft.com/json/help/html/SelectToken.htm

* Added unit tests

* Addressed the comments

* Addressed the comments

* Update JSONPathMatcher.cs

src/WireMock.Net/Matchers/JSONPathMatcher.cs

@@ -123,7 +123,12 @@ public class JsonPathMatcher : IStringMatcher, IObjectMatcher
     {
         var array = ConvertJTokenToJArrayIfNeeded(jToken);
 
-        return MatchScores.ToScore(_patterns.Select(pattern => array.SelectToken(pattern.GetPattern())?.Any() == true).ToArray(), MatchOperator);
+        // The SelectToken method can accept a string path to a child token ( i.e. "Manufacturers[0].Products[0].Price"). In that case it will return a JValue (some type) which does not implement the IEnumerable interface.
+        // Using ?.Any() == true relays that we use a JSONPath queries and the SelectToken will return a JObject ( implements the IEnumerable interface).
+        // So the current code works only when the JSONPath is expression and not when we pass a valid string path to child. 
+        // My suggestion is to roll back to != null to cover the both cases.
+ 
+        return MatchScores.ToScore(_patterns.Select(pattern => array.SelectToken(pattern.GetPattern()) != null ).ToArray(), MatchOperator);
     }
 
     // https://github.com/WireMock-Net/WireMock.Net/issues/965
@@ -149,4 +154,4 @@ public class JsonPathMatcher : IStringMatcher, IObjectMatcher
 
         return jToken;
     }
-}
+}

test/WireMock.Net.Tests/Matchers/JsonPathMatcherTests.cs

@@ -200,4 +200,128 @@ public class JsonPathMatcherTests
         // Assert
         Check.That(match).IsEqualTo(0.0);
     }
-}
+
+    [Fact]
+    public void JsonPathMatcher_IsMatch_ArrayOneLevel()
+    {
+        // Arrange 
+        var matcher = new JsonPathMatcher("$.arr[0].line1");
+        
+        // Act 
+        double match = matcher.IsMatch(JObject.Parse(@"{
+            ""name"": ""PathSelectorTest"",
+            ""test"": ""test"",
+            ""test2"": ""test2"",
+            ""arr"": [{
+                ""line1"": ""line1"",
+            }]
+        }"));
+
+        // Assert
+        Check.That(match).IsEqualTo(1.0); 
+    }
+    
+    [Fact]
+    public void JsonPathMatcher_IsMatch_ObjectMatch()
+    {
+        // Arrange 
+        var matcher = new JsonPathMatcher("$.test");
+        
+        // Act 
+        double match = matcher.IsMatch(JObject.Parse(@"{
+            ""name"": ""PathSelectorTest"",
+            ""test"": ""test"",
+            ""test2"": ""test2"",
+            ""arr"": [
+                {
+                    ""line1"": ""line1"",
+                }
+            ]
+        }"));
+
+        // Assert 
+         Check.That(match).IsEqualTo(1.0); 
+    }
+
+    [Fact]
+    public void JsonPathMatcher_IsMatch_DoesntMatch()
+    {
+        // Arrange 
+        var matcher = new JsonPathMatcher("$.test3");
+        
+        // Act 
+        double match = matcher.IsMatch(JObject.Parse(@"{
+            ""name"": ""PathSelectorTest"",
+            ""test"": ""test"",
+            ""test2"": ""test2"",
+            ""arr"": [
+                {
+                    ""line1"": ""line1"",
+                }
+            ]
+        }"));
+    
+        // Assert 
+        Check.That(match).IsEqualTo(0.0); 
+    }
+
+    [Fact]
+    public void JsonPathMatcher_IsMatch_DoesntMatchInArray()
+    {
+        // Arrange 
+        var matcher = new JsonPathMatcher("$arr[0].line1");
+        
+        // Act 
+        double match = matcher.IsMatch(JObject.Parse(@"{
+            ""name"": ""PathSelectorTest"",
+            ""test"": ""test"",
+            ""test2"": ""test2"",
+            ""arr"": []
+        }"));
+
+        // Assert 
+        Check.That(match).IsEqualTo(0.0); 
+    }
+    
+    [Fact]
+    public void JsonPathMatcher_IsMatch_DoesntMatchNoObjectsInArray()
+    {
+        // Arrange 
+        var matcher = new JsonPathMatcher("$arr[2].line1");
+        
+        // Act 
+        double match = matcher.IsMatch(JObject.Parse(@"{
+            ""name"": ""PathSelectorTest"",
+            ""test"": ""test"",
+            ""test2"": ""test2"",
+            ""arr"": []
+        }"));
+
+        // Assert 
+        Check.That(match).IsEqualTo(0.0); 
+    }
+
+    [Fact]
+    public void JsonPathMatcher_IsMatch_NestedArrays()
+    {
+        // Arrange 
+        var matcher = new JsonPathMatcher("$.arr[0].sub[0].subline1");
+        
+        // Act 
+        double match = matcher.IsMatch(JObject.Parse(@"{
+            ""name"": ""PathSelectorTest"",
+            ""test"": ""test"",
+            ""test2"": ""test2"",
+            ""arr"": [{
+                ""line1"": ""line1"",
+                ""sub"":[
+                {
+                    ""subline1"":""subline1""
+                }]
+            }]
+        }"));
+
+        // Assert 
+      Check.That(match).IsEqualTo(1.0); 
+    }
+}