Method json() to parse JSON strings

- Parse a JSON string into array
- Test

src/Expectation.php

@@ -60,6 +60,17 @@ final class Expectation
         return new self($value);
     }
 
+    /**
+     * Parses Json String to Array.
+     */
+    public function json(): Expectation
+    {
+        Assert::assertIsString($this->value);
+        Assert::assertJson($this->value);
+
+        return new self(json_decode($this->value, true));
+    }
+
     /**
      * Dump the expectation value and end the script.
      *

tests/Features/Expect/json.php

@@ -0,0 +1,14 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+test('it properly parses json string', function () {
+    expect('{"name":"Nuno"}')
+        ->json()
+        ->name
+        ->toBe('Nuno');
+});
+
+test('fails with broken json string', function () {
+    expect('{":"Nuno"}')->json();
+})->throws(ExpectationFailedException::class);