[Mime] Add DataPart::setContentId()

Author: fabpot

Part/DataPart.php

@@ -89,6 +89,20 @@ public function asInline(): static
         return $this->setDisposition('inline');
     }
 
+    /**
+     * @return $this
+     */
+    public function setContentId(string $cid): static
+    {
+        if (!str_contains($cid, '@')) {
+            throw new InvalidArgumentException(sprintf('Invalid cid "%s".', $cid));
+        }
+
+        $this->cid = $cid;
+
+        return $this;
+    }
+
     public function getContentId(): string
     {
         return $this->cid ?: $this->cid = $this->generateContentId();

Tests/Part/DataPartTest.php

@@ -166,6 +166,22 @@ public function testHasContentId()
         $this->assertTrue($p->hasContentId());
     }
 
+    public function testSetContentId()
+    {
+        $p = new DataPart('content');
+        $p->setContentId('test@test');
+        $this->assertTrue($p->hasContentId());
+        $this->assertSame('test@test', $p->getContentId());
+    }
+
+    public function testSetContentIdInvalid()
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        $p = new DataPart('content');
+        $p->setContentId('test');
+    }
+
     public function testGetFilename()
     {
         $p = new DataPart('content', null);