fix: Fixes serialization of invalid items (e.g., functions) to return…

… empty array. (#18)

src/Internal/JsonSerializer.php

@@ -8,15 +8,11 @@
 {
     public function serialize(array $data): string
     {
-        $isSingleItem = count($data) === 1;
-        $dataToSerialize = $isSingleItem ? ($data[0] ?? null) : $data;
+        $isSingleItem = static fn(array $data): bool => array_keys($data) !== range(0, count($data) - 1);
+        $dataToSerialize = $isSingleItem($data) ? $data : ($data[0] ?? null);
 
         $json = json_encode($dataToSerialize, JSON_PRESERVE_ZERO_FRACTION);
 
-        if (!is_string($json) || $json === 'null') {
-            return $isSingleItem ? '{}' : '[]';
-        }
-
-        return $json;
+        return is_string($json) ? $json : '{}';
     }
 }

tests/IterableSerializerTest.php

@@ -82,7 +82,7 @@ public function testSerializeMultipleInvalidItemsReturnsEmptyJsonArray(): void
         $actual = $serializer->toJson();
 
         /** @Then the output should be an empty JSON array */
-        self::assertSame('[[],[]]', $actual);
+        self::assertSame('[]', $actual);
     }
 
     public static function toJsonDataProvider(): array

tests/Models/Serializable/Decimal.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TinyBlocks\Serializer\Models\Serializable;
+
+use TinyBlocks\Serializer\Serializer;
+use TinyBlocks\Serializer\SerializerAdapter;
+
+final readonly class Decimal implements Serializer
+{
+    use SerializerAdapter;
+
+    public function __construct(public float $value)
+    {
+    }
+}

tests/SerializerAdapterTest.php

@@ -9,45 +9,46 @@
 use TinyBlocks\Serializer\Models\Serializable\Address;
 use TinyBlocks\Serializer\Models\Serializable\Addresses;
 use TinyBlocks\Serializer\Models\Serializable\Country;
+use TinyBlocks\Serializer\Models\Serializable\Decimal;
 use TinyBlocks\Serializer\Models\Serializable\Service;
 use TinyBlocks\Serializer\Models\Serializable\Shipping;
 use TinyBlocks\Serializer\Models\Serializable\State;
 
 final class SerializerAdapterTest extends TestCase
 {
-    #[DataProvider('shippingDataProviderForArray')]
-    public function testSerializeToArray(Shipping $shipping, array $expected): void
+    #[DataProvider('dataProviderForToArray')]
+    public function testSerializeToArray(Serializer $object, array $expected): void
     {
-        /** @When the toArray method is called on the Shipping object */
-        $actual = $shipping->toArray();
+        /** @When the toArray method is called on the object */
+        $actual = $object->toArray();
 
         /** @Then the result should match the expected structure */
         self::assertSame($expected, $actual);
     }
 
-    #[DataProvider('shippingDataProviderForJson')]
-    public function testSerializeToJson(Shipping $shipping, string $expected): void
+    #[DataProvider('dataProviderForToJson')]
+    public function testSerializeToJson(Serializer $object, string $expected): void
     {
-        /** @When the toJson method is called on the Shipping object */
-        $actual = $shipping->toJson();
+        /** @When the toJson method is called on the object */
+        $actual = $object->toJson();
 
         /** @Then the result should match the expected JSON string */
         self::assertJsonStringEqualsJsonString($expected, $actual);
     }
 
-    public function testSerializeSingleInvalidItemReturnsEmptyJsonObject(): void
+    public function testSerializeSingleInvalidItemReturnsReturnsEmptyArray(): void
     {
         /** @Given a single invalid item (e.g., a function that cannot be serialized) */
         $service = new Service(action: fn(): int => 0);
 
-        /** @When attempting to serialize the invalid item */
+        /** @When attempting to serialize the object with the invalid item */
         $actual = $service->toJson();
 
-        /** @Then the output should be an empty JSON object */
-        self::assertSame('{}', $actual);
+        /** @Then the invalid item should be serialized as an empty array in the JSON output */
+        self::assertSame('{"action":[]}', $actual);
     }
 
-    public static function shippingDataProviderForArray(): array
+    public static function dataProviderForToArray(): array
     {
         $shippingWithNoAddresses = new Shipping(id: 1, addresses: new Addresses());
         $shippingWithSingleAddress = new Shipping(
@@ -87,12 +88,16 @@ public static function shippingDataProviderForArray(): array
         );
 
         return [
+            'Decimal object'                          => [
+                'object'   => new Decimal(value: 9.99),
+                'expected' => ['value' => 9.99]
+            ],
             'Shipping object with no addresses'       => [
-                'shipping' => $shippingWithNoAddresses,
+                'object'   => $shippingWithNoAddresses,
                 'expected' => ['id' => 1, 'addresses' => []]
             ],
             'Shipping object with a single address'   => [
-                'shipping' => $shippingWithSingleAddress,
+                'object'   => $shippingWithSingleAddress,
                 'expected' => [
                     'id'        => 2,
                     'addresses' => [
@@ -107,7 +112,7 @@ public static function shippingDataProviderForArray(): array
                 ]
             ],
             'Shipping object with multiple addresses' => [
-                'shipping' => $shippingWithMultipleAddresses,
+                'object'   => $shippingWithMultipleAddresses,
                 'expected' => [
                     'id'        => 100000,
                     'addresses' => [
@@ -131,15 +136,19 @@ public static function shippingDataProviderForArray(): array
         ];
     }
 
-    public static function shippingDataProviderForJson(): array
+    public static function dataProviderForToJson(): array
     {
         return [
+            'Decimal object'                          => [
+                'object'   => new Decimal(value: 9.99),
+                'expected' => '{"value":9.99}'
+            ],
             'Shipping object with no addresses'       => [
-                'shipping' => new Shipping(id: 1, addresses: new Addresses()),
+                'object'   => new Shipping(id: 1, addresses: new Addresses()),
                 'expected' => '{"id":1,"addresses":[]}'
             ],
             'Shipping object with a single address'   => [
-                'shipping' => new Shipping(
+                'object'   => new Shipping(
                     id: 2,
                     addresses: new Addresses(
                         elements: [
@@ -156,7 +165,7 @@ public static function shippingDataProviderForJson(): array
                 'expected' => '{"id":2,"addresses":[{"city":"São Paulo","state":"SP","street":"Avenida Paulista","number":100,"country":"BR"}]}'
             ],
             'Shipping object with multiple addresses' => [
-                'shipping' => new Shipping(
+                'object'   => new Shipping(
                     id: 100000,
                     addresses: new Addresses(
                         elements: [