Support int literals in JSON content being assigned to double fields (#34)

Right now `{'value': 0}` cannot be assigned to a double.

Also improve types a bit in test_utils

Author: kevmoo

CHANGELOG.md

@@ -3,6 +3,8 @@
 * Simplify the serialization of `Map` instances when no conversion is required
   for `values`.
 
+* Handle `int` literals in JSON being assigned to `double` fields.
+
 ## 0.2.2
 
 * Enable support for `enum` values.

lib/src/type_helpers/value_helper.dart

@@ -1,4 +1,5 @@
 import 'package:analyzer/dart/element/type.dart';
+import 'package:source_gen/source_gen.dart' show TypeChecker;
 import '../type_helper.dart';
 
 class ValueHelper extends TypeHelper {
@@ -20,6 +21,9 @@ class ValueHelper extends TypeHelper {
     if (targetType.isDynamic || targetType.isObject) {
       // just return it as-is. We'll hope it's safe.
       return expression;
+    } else if (const TypeChecker.fromRuntime(double)
+        .isExactlyType(targetType)) {
+      return '($expression as num).toDouble()';
     } else if (simpleJsonTypeChecker.isAssignableFromType(targetType)) {
       return '$expression as $targetType';
     }

test/json_serializable_integration_test.dart

@@ -104,4 +104,34 @@ void main() {
       roundTripItem(item);
     });
   });
+
+  group('Numbers', () {
+    roundTripNumber(Numbers p) {
+      roundTripObject(p, (json) => new Numbers.fromJson(json));
+    }
+
+    test('simple', () {
+      roundTripNumber(new Numbers()
+        ..nums = [0, 0.0]
+        ..doubles = [0.0]
+        ..ints = [0]);
+    });
+
+    test('support ints as doubles', () {
+      var value = {
+        'doubles': [0, 0.0]
+      };
+
+      roundTripNumber(new Numbers.fromJson(value));
+    });
+
+    test('does not support doubles as ints', () {
+      var value = {
+        'ints': [0.0, 0],
+      };
+
+      expect(() => new Numbers.fromJson(value),
+          throwsA(new isInstanceOf<CastError>()));
+    });
+  });
 }

test/test_files/json_test_example.dart

@@ -102,3 +102,21 @@ class Platform {
 
   String toJson() => description;
 }
+
+@JsonSerializable()
+class Numbers extends Object with _$NumbersSerializerMixin {
+  List<int> ints;
+  List<num> nums;
+  List<double> doubles;
+
+  Numbers();
+
+  factory Numbers.fromJson(Map<String, dynamic> json) =>
+      _$NumbersFromJson(json);
+
+  bool operator ==(Object other) =>
+      other is Numbers &&
+      _deepEquals(ints, other.ints) &&
+      _deepEquals(nums, other.nums) &&
+      _deepEquals(doubles, other.doubles);
+}

test/test_files/json_test_example.g.dart

@@ -73,7 +73,7 @@ Iterable<Element> _getElements(CompilationUnitMember member) {
   return [element];
 }
 
-void roundTripObject(object, factory(Map<String, dynamic> json)) {
+void roundTripObject<T>(T object, T factory(Map<String, dynamic> json)) {
   var json = loudEncode(object);
 
   var person2 = factory(JSON.decode(json) as Map<String, dynamic>);
@@ -86,7 +86,7 @@ void roundTripObject(object, factory(Map<String, dynamic> json)) {
 }
 
 /// Prints out nested causes before throwing `JsonUnsupportedObjectError`.
-String loudEncode(object) {
+String loudEncode(Object object) {
   try {
     return const JsonEncoder.withIndent(' ').convert(object);
   } on JsonUnsupportedObjectError catch (e) {