From 40a4fa39b7ef09ee1749ae48a71a12c55505fc9a Mon Sep 17 00:00:00 2001
From: jrfnl <jrfnl@users.noreply.github.com>
Date: Sun, 4 Jul 2021 20:42:48 +0200
Subject: [PATCH] AddStringAttachmentTest: improve original test

This expands the assertions executed in this test to cover the code under test more comprehensively.
---
 test/PHPMailer/AddStringAttachmentTest.php | 54 +++++++++++++++++++---
 1 file changed, 48 insertions(+), 6 deletions(-)

diff --git a/test/PHPMailer/AddStringAttachmentTest.php b/test/PHPMailer/AddStringAttachmentTest.php
index 414b9e8d..8ede72d1 100644
--- a/test/PHPMailer/AddStringAttachmentTest.php
+++ b/test/PHPMailer/AddStringAttachmentTest.php
@@ -24,21 +24,63 @@ final class AddStringAttachmentTest extends PreSendTestCase
 {
 
     /**
-     * Simple plain string attachment test.
+     * Test successfully adding a simple plain string attachment.
      */
-    public function testPlainStringAttachment()
+    public function testAddPlainStringAttachment()
     {
-        $this->Mail->Body = 'Here is the text body';
-        $this->Mail->Subject .= ': Plain + StringAttachment';
-
         $sAttachment = 'These characters are the content of the ' .
             "string attachment.\nThis might be taken from a " .
             'database or some other such thing. ';
 
-        $this->Mail->addStringAttachment($sAttachment, 'string_attach.txt');
+        $expected   = [
+            0 => $sAttachment,
+            1 => 'string_attach.txt',
+            2 => 'string_attach.txt',
+            3 => 'base64',
+            4 => 'text/plain',
+            5 => true,
+            6 => 'attachment',
+            7 => 0,
+        ];
 
+        $this->Mail->Body = 'Here is the text body';
+        $this->Mail->Subject .= ': Plain + StringAttachment';
+
+        // Test attaching the plain string attachment.
+        $result = $this->Mail->addStringAttachment($sAttachment, 'string_attach.txt');
+
+        self::assertTrue($result, $this->Mail->ErrorInfo);
+        self::assertTrue($this->Mail->attachmentExists(), 'Plain text attachment not present in attachments array');
+
+        $attachments = $this->Mail->getAttachments();
+        self::assertIsArray($attachments, 'Attachments is not an array');
+        self::assertArrayHasKey(0, $attachments, 'Attachments does not have the expected array entry');
+        self::assertSame($expected, $attachments[0], 'Attachment info does not match the expected array');
+
+        // Test that the plain text attachment was correctly added to the message body.
         $this->buildBody();
         self::assertTrue($this->Mail->preSend(), $this->Mail->ErrorInfo);
+
+        $sendMessage = $this->Mail->getSentMIMEMessage();
+        $LE          = PHPMailer::getLE();
+
+        self::assertStringContainsString(
+            'Content-Type: text/plain; name=string_attach.txt' . $LE,
+            $sendMessage,
+            'Embedded image header content type incorrect.'
+        );
+
+        self::assertStringNotContainsString(
+            'Content-ID: ' . $LE,
+            $sendMessage,
+            'Embedded image header content ID not empty.'
+        );
+
+        self::assertStringContainsString(
+            'Content-Disposition: attachment; filename=string_attach.txt' . $LE,
+            $sendMessage,
+            'Embedded image header content disposition incorrect.'
+        );
     }
 
     /**