From 4b29c0514ee3764f679a87968452b81818b04131 Mon Sep 17 00:00:00 2001
From: Dave Earley <dave.m.earley@gmail.com>
Date: Mon, 22 Jun 2020 00:05:00 +0100
Subject: [PATCH] Check for DNS A/AAA records (closes #22)

---
 src/EmailAddress.php                         |  4 ++--
 src/Validations/MxRecordsValidator.php       | 14 +++++++++++---
 tests/Validations/MxRecordsValidatorTest.php | 14 ++++++++++++--
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/src/EmailAddress.php b/src/EmailAddress.php
index 86f4880..81525ee 100644
--- a/src/EmailAddress.php
+++ b/src/EmailAddress.php
@@ -35,10 +35,10 @@ private function getEmailPart(int $partNumber): string
         return (explode('@', $this->emailAddress))[$partNumber];
     }
 
-    public function getHostPart(): ?string
+    public function getHostPart(bool $returnFqdn = false): ?string
     {
         if ($this->isValidEmailAddressFormat()) {
-            return $this->getEmailPart(self::EMAIL_HOST_PART);
+            return $this->getEmailPart(self::EMAIL_HOST_PART) . ($returnFqdn ? '.' : '');
         }
 
         return null;
diff --git a/src/Validations/MxRecordsValidator.php b/src/Validations/MxRecordsValidator.php
index d5e7812..704652a 100644
--- a/src/Validations/MxRecordsValidator.php
+++ b/src/Validations/MxRecordsValidator.php
@@ -6,6 +6,8 @@
 
 class MxRecordsValidator extends Validator implements ValidatorInterface
 {
+    private const VALID_DNS_RECORDS = ['MX', 'A', 'AAAA', 'NS'];
+
     public function getValidatorName(): string
     {
         return 'valid_mx_records'; // @codeCoverageIgnore
@@ -13,11 +15,17 @@ public function getValidatorName(): string
 
     public function getResultResponse(): bool
     {
-        if ($this->getEmailAddress()->isValidEmailAddressFormat()) {
-            return $this->checkDns($this->getEmailAddress()->getHostPart(), 'MX');
+        if (!$this->getEmailAddress()->isValidEmailAddressFormat()) {
+            return false; // @codeCoverageIgnore
+        }
+
+        $results = [];
+        foreach (self::VALID_DNS_RECORDS as $dns) {
+            $results[] = $this->checkDns($this->getEmailAddress()->getHostPart(true), $dns);
         }
 
-        return false; // @codeCoverageIgnore
+        // To be considered valid we needs an NS record and at least one MX, A or AAA record
+        return count(array_filter($results)) >= 2;
     }
 
     protected function checkDns(string $host, string $type = null): bool
diff --git a/tests/Validations/MxRecordsValidatorTest.php b/tests/Validations/MxRecordsValidatorTest.php
index 7cb45ca..3f916f0 100644
--- a/tests/Validations/MxRecordsValidatorTest.php
+++ b/tests/Validations/MxRecordsValidatorTest.php
@@ -16,7 +16,12 @@ class MxRecordsValidatorTest extends TestCase
 
     public function testMxRecordIsChecked(): void
     {
-        $this->mxValidator->shouldReceive('checkDns')->with('dave@gmail.com', 'MX');
+        foreach (['MX', 'AAAA', 'NS', 'A'] as $dns) {
+            $this->mxValidator
+                ->shouldReceive('checkDns')
+                ->with('gmail.com.', $dns);
+        }
+
         $this->mxValidator->getResultResponse();
     }
 
@@ -26,6 +31,11 @@ protected function setUp(): void
             new EmailAddress('dave@gmail.com'),
         ])
             ->shouldAllowMockingProtectedMethods()
-            ->makePartial();
+            ->shouldReceive('getResultResponse')
+            ->passthru()
+            ->getMock()
+            ->shouldReceive('getEmailAddress')
+            ->passthru()
+            ->getMock();
     }
 }
\ No newline at end of file