Base Unit class implements JsonSerializable now

src/Unit.php

@@ -1,13 +1,14 @@
 <?php
 namespace PhpUnitConversion;
 
+use JsonSerializable;
 use InvalidArgumentException;
 use PhpUnitConversion\Map as UnitMap;
 use PhpUnitConversion\Exception\InvocationException;
 use PhpUnitConversion\Exception\UnsupportedUnitException;
 use PhpUnitConversion\Exception\UnsupportedConversionException;
 
-class Unit
+class Unit implements JsonSerializable
 {
     /** @var float */
     protected $value;
@@ -467,4 +468,16 @@ public function __toString()
         $symbol = $this->getSymbol();
         return (string)$this->getValue() . ($symbol ? ' ' . $symbol : '');
     }
+
+    /**
+     * @return array
+     */
+    public function jsonSerialize()
+    {
+        return [
+            'value' => $this->getValue(),
+            'symbol' => $this->getSymbol(),
+            'label' => $this->getLabel(),
+        ];
+    }
 }

tests/UnitTest.php

@@ -108,6 +108,20 @@ public function testToString()
         $this->assertEquals('1 u', (string)$unit);
     }
 
+    public function testToJson()
+    {
+        $unit = new MyUnitType\OneUnit(1);
+
+        $expected = [
+            'value' => 1,
+            'symbol' => 'u',
+            'label' => 'unit',
+        ];
+
+        $this->assertEquals($expected, $unit->jsonSerialize());
+        $this->assertEquals(json_encode($expected), json_encode($unit));
+    }
+
     public function testInvalidInvocation()
     {
         $this->expectException(Exception::class);