Add test for personal_lockAccount

Change:
* Add test for personal_lockAccount

examples/personal.php

@@ -38,3 +38,16 @@ $web3->eth->getBalance($newAccount, function ($err, $balance) {
 	}
 	echo 'Balance: ' . $balance->toString() . PHP_EOL;
 });
+
+// remember to lock account after transaction
+$personal->lockAccount($newAccount, function ($err, $locked) {
+	if ($err !== null) {
+		echo 'Error: ' . $err->getMessage();
+		return;
+	}
+	if ($locked) {
+        echo 'New account is locked!' . PHP_EOL;
+	} else {
+	    echo 'New account isn\'t locked' . PHP_EOL;
+	}
+});

src/Methods/Personal/LockAccount.php

@@ -11,14 +11,9 @@
 
 namespace Web3\Methods\Personal;
 
-use InvalidArgumentException;
 use Web3\Methods\EthMethod;
 use Web3\Validators\AddressValidator;
-use Web3\Validators\StringValidator;
-use Web3\Validators\QuantityValidator;
 use Web3\Formatters\AddressFormatter;
-use Web3\Formatters\StringFormatter;
-use Web3\Formatters\NumberFormatter;
 
 class LockAccount extends EthMethod
 {

test/unit/PersonalApiTest.php

@@ -121,6 +121,39 @@ class PersonalApiTest extends TestCase
         });
     }
 
+    /**
+     * testLockAccount
+     * 
+     * @return void
+     */
+    public function testLockAccount()
+    {
+        $personal = $this->personal;
+
+        // create account
+        $personal->newAccount('123456', function ($err, $account) {
+            if ($err !== null) {
+                return $this->fail($err->getMessage());
+            }
+            $this->newAccount = $account;
+            $this->assertTrue(is_string($account));
+        });
+
+        $personal->unlockAccount($this->newAccount, '123456', function ($err, $unlocked) {
+            if ($err !== null) {
+                return $this->fail($err->getMessage());
+            }
+            $this->assertTrue($unlocked);
+        });
+
+        $personal->lockAccount($this->newAccount, function ($err, $locked) {
+            if ($err !== null) {
+                return $this->fail($err->getMessage());
+            }
+            $this->assertTrue($locked);
+        });
+    }
+
     /**
      * testSendTransaction
      *