Stops null values from overriding existing values (#8)

Author: Kralizek

src/Objects/Internal/JsonConfigurationSerializer.cs

@@ -108,7 +108,13 @@ private void VisitPrimitive(JValue data)
                 {
                     throw new FormatException($"A duplicate key '{key}' was found.");
                 }
-                _data[key] = data.ToString(CultureInfo.InvariantCulture);
+
+                var stringValue = data.ToString(CultureInfo.InvariantCulture);
+
+                if (!string.IsNullOrEmpty(stringValue))
+                {
+                    _data[key] = stringValue;
+                }
             }
 
             private void EnterContext(string context)

tests/Tests.Objects/ConfigurationTests.cs

@@ -123,5 +123,37 @@ public void Object_can_be_retrieved_from_configuration(ConfigurationBuilder conf
         }
 
         bool Comparison(ObjectWithSimpleProperties first, ObjectWithSimpleProperties second) => first.Text == second.Text && first.Value == second.Value;
+
+        
+        [Test, CustomAutoData]
+        [Property("Issue", "3")]
+        public void Null_values_should_not_override_existing_values(ConfigurationBuilder configurationBuilder, ObjectWithSimpleProperties testSource)
+        {
+            configurationBuilder.AddObject(testSource);
+
+            configurationBuilder.AddObject(new ObjectWithSimpleProperties{ Text = null, Value = testSource.Value });
+
+            var configuration = configurationBuilder.Build();
+
+            var result = configuration.Get<ObjectWithSimpleProperties>();
+
+            Assert.That(result.Text, Is.EqualTo(testSource.Text));
+            Assert.That(result.Value, Is.EqualTo(testSource.Value));
+        }
+
+        [Test, CustomAutoData]
+        [Property("Issue", "3")]
+        public void Null_values_should_not_override_existing_values(ConfigurationBuilder configurationBuilder, ObjectWithSimpleIntArray testSource)
+        {
+            configurationBuilder.AddObject(testSource);
+
+            configurationBuilder.AddObject(new ObjectWithSimpleIntArray { Values = new int[0] });
+
+            var configuration = configurationBuilder.Build();
+
+            var result = configuration.Get<ObjectWithSimpleIntArray>();
+
+            Assert.That(result.Values, Is.EquivalentTo(testSource.Values));
+        }
     }
 }

tests/Tests.Objects/Internal/JsonConfigurationSerializerTests.cs

@@ -83,5 +83,19 @@ public void Importing_same_object_twice_should_not_throw(JsonConfigurationSerial
             Assert.That(result[$"{rootSectionName}:{nameof(testSource.Items)}:0:{nameof(ObjectWithSimpleProperties.Text)}"], Is.EqualTo($"{testSource.Items[0].Text}"));
             Assert.That(result[$"{rootSectionName}:{nameof(testSource.Items)}:0:{nameof(ObjectWithSimpleProperties.Value)}"], Is.EqualTo($"{testSource.Items[0].Value}"));
         }
+
+        [Test, CustomAutoData]
+        [Property("Issue", "2")]
+        public void Null_values_should_not_be_added(JsonConfigurationSerializer sut, ObjectWithSimpleProperties testSource, string rootSectionName)
+        {
+            testSource.Text = null;
+
+            var result = sut.Serialize(testSource, rootSectionName);
+
+            Assert.That(result, Does.Not.ContainKey($"{rootSectionName}:{nameof(testSource.Text)}"));
+            Assert.That(result, Contains.Key($"{rootSectionName}:{nameof(testSource.Value)}"));
+
+            Assert.That(result[$"{rootSectionName}:{nameof(testSource.Value)}"], Is.EqualTo($"{testSource.Value}"));
+        }
     }
 }