Add submitblock command

src/Command/Mining/SubmitBlock.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace ZenCash\Rpc\Command\Mining;
+
+use ZenCash\Rpc\Command;
+
+final class SubmitBlock implements Command
+{
+    private const METHOD = 'submitblock';
+    private $hexData;
+
+    public function __construct(string $hexData)
+    {
+        $this->hexData = $hexData;
+    }
+
+    public function jsonSerialize(): object
+    {
+        return (object) [
+            'jsonrpc' => Command::JSON_RPC_VERSION,
+            'id'      => Command::ID,
+            'method'  => self::METHOD,
+            'params' => [$this->hexData]
+        ];
+    }
+}

tests/Command/Mining/SubmitBlockTest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace ZenCash\Rpc\Command\Mining;
+
+use PHPUnit\Framework\TestCase;
+
+class SubmitBlockTest extends TestCase
+{
+    public function test_serialize_returns_expected_object()
+    {
+        $expected = (object) [
+            'jsonrpc' => '1.0',
+            'id'      => 'curl',
+            'method'  => 'submitblock',
+            'params' => ['mytestdata']
+        ];
+
+        $this->assertEquals($expected, (new SubmitBlock('mytestdata'))->jsonSerialize());
+    }
+}