add test case for nsnull

Author: CoderMJLee

KakaJSON/Convert/Convertible.swift

@@ -217,8 +217,14 @@ extension Convertible {
     }
 
     mutating func kj_convert(from json: [String: Any]) {
-        guard let mt = Metadata.type(self) as? ModelType,
-            let properties = mt.properties else { return }
+        guard let mt = Metadata.type(self) as? ModelType else {
+            Logger.warnning("Not a class or struct instance.")
+            return
+        }
+        guard let properties = mt.properties else {
+            Logger.warnning("Don't have any property.")
+            return
+        }
 
         // get data address
         let model = _ptr()
@@ -299,9 +305,14 @@ extension Convertible {
 // MARK: - Model -> JSON
 extension Convertible {
     func kj_JSONObject() -> [String: Any]? {
-        guard let mt = Metadata.type(self) as? ModelType,
-            let properties = mt.properties
-            else { return nil }
+        guard let mt = Metadata.type(self) as? ModelType else {
+            Logger.warnning("Not a class or struct instance.")
+            return nil
+        }
+        guard let properties = mt.properties else {
+            Logger.warnning("Don't have any property.")
+            return nil
+        }
 
         kj_willConvertToJSON()
 

KakaJSON/Convert/Values.swift

@@ -14,6 +14,8 @@ import CoreGraphics
 public struct Values {
     static func value(_ val: Any?, _ type: Any.Type) -> Any? {
         guard let v = val.kj_value else { return nil }
+        if v is NSNull { return v }
+        
         if Swift.type(of: v) == type { return v }
 
         switch type {
@@ -35,6 +37,7 @@ public struct Values {
 
     static func JSONValue(_ value: Any?) -> Any? {
         guard let v = value.kj_value else { return nil }
+        if v is NSNull { return nil }
 
         switch v {
         case let num as NumberValue: return _JSONValue(from: num)

KakaJSON/DevGuidline.h

@@ -6,6 +6,16 @@
 //  Copyright © 2019 MJ Lee. All rights reserved.
 //
 
+/*
+ Metadata Reference:
+ 0. https://github.com/apple/swift/blob/master/docs/ABI/TypeMetadata.rst
+ 1. https://github.com/apple/swift/blob/master/include/swift/ABI/MetadataKind.def
+ 2. https://github.com/apple/swift/blob/master/include/swift/ABI/Metadata.h
+ 3. https://github.com/apple/swift/blob/master/include/swift/ABI/MetadataValues.h
+ 4. https://github.com/apple/swift/blob/master/utils/dtrace/runtime.d
+ 5. https://github.com/apple/swift/blob/master/include/swift/Reflection/Records.h
+ */
+
 1. 提交代码之前，请务必先保证在真机、模拟器上通过所有的测试用例（Debug+Release模式）
 
 2. 命名规范

KakaJSON/Global/JSON.swift

@@ -6,16 +6,6 @@
 //  Copyright © 2019 MJ Lee. All rights reserved.
 //
 
-/*
- Reference:
- 0. https://github.com/apple/swift/blob/master/docs/ABI/TypeMetadata.rst
- 1. https://github.com/apple/swift/blob/master/include/swift/ABI/MetadataKind.def
- 2. https://github.com/apple/swift/blob/master/include/swift/ABI/Metadata.h
- 3. https://github.com/apple/swift/blob/master/include/swift/ABI/MetadataValues.h
- 4. https://github.com/apple/swift/blob/master/utils/dtrace/runtime.d
- 5. https://github.com/apple/swift/blob/master/include/swift/Reflection/Records.h
- */
-
 // MARK: Model -> JSON
 public func JSONObject<M: Convertible>(from model: M) -> [String: Any]? {
     return model.kj_JSONObject()

KakaJSONDemo.xcodeproj/xcshareddata/xcschemes/KakaJSONDemo.xcscheme

@@ -52,7 +52,7 @@
       </AdditionalOptions>
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"

KakaJSONTests/JSON_To_Model/JTM_01_Basic.swift

@@ -80,6 +80,27 @@ class JTM_01_Basic: XCTestCase {
         XCTAssert(cat?.weight == weight)
     }
 
+    // MARK: - NSNull
+    func testNSNull() {
+        struct Cat: Convertible {
+            var weight: Double = 0.0
+            var name: String = "xx"
+            var data: NSNull?
+        }
+        
+        let json: [String: Any] = [
+            "name": NSNull(),
+            "weight": 6.6,
+            "data": NSNull()
+        ]
+        
+        let cat = json.kj.model(Cat.self)
+        // convert failed, keep default value
+        XCTAssert(cat?.name == "xx")
+        XCTAssert(cat?.weight == 6.6)
+        XCTAssert(cat?.data == NSNull())
+    }
+    
     // MARK: - let
     func testLet() {
         struct Cat: Convertible {

README.md

@@ -41,6 +41,7 @@ Or you can login Xcode with your GitHub account. just search **KakaJSON**.
   - [Class Type](#class-type)
   - [Inheritance](#inheritance)
   - [let](#let)
+  - [NSNull](#nsnull)
   - [JSONString](#jsonstring)
   - [JSONData](#jsondata)
   - [Nested Model 1](#nested-model-1)
@@ -352,6 +353,27 @@ let json = ...
 let cat = json.kj.model(Cat.self)
 ```
 
+### NSNull
+```swift
+struct Cat: Convertible {
+    var weight: Double = 0.0
+    var name: String = "xx"
+    var data: NSNull?
+}
+
+let json: [String: Any] = [
+    "name": NSNull(),
+    "weight": 6.6,
+    "data": NSNull()
+]
+
+let cat = json.kj.model(Cat.self)
+// convert failed, keep default value
+XCTAssert(cat?.name == "xx")
+XCTAssert(cat?.weight == 6.6)
+XCTAssert(cat?.data == NSNull())
+```
+
 ### JSONString
 ```swift
 // jsonString can alse be NSString, NSMutableString