diff --git a/src/PhpSpreadsheet/Helper/Sample.php b/src/PhpSpreadsheet/Helper/Sample.php
index a91b195e2..c84c39303 100644
--- a/src/PhpSpreadsheet/Helper/Sample.php
+++ b/src/PhpSpreadsheet/Helper/Sample.php
@@ -71,7 +71,7 @@ class Sample
     /**
      * Returns an array of all known samples.
      *
-     * @return string[] [$name => $path]
+     * @return string[][] [$name => $path]
      */
     public function getSamples()
     {
@@ -132,6 +132,11 @@ class Sample
         $this->logEndingNotes();
     }
 
+    protected function isDirOrMkdir(string $folder): bool
+    {
+        return \is_dir($folder) || \mkdir($folder);
+    }
+
     /**
      * Returns the temporary directory and make sure it exists.
      *
@@ -140,10 +145,8 @@ class Sample
     private function getTemporaryFolder()
     {
         $tempFolder = sys_get_temp_dir() . '/phpspreadsheet';
-        if (!is_dir($tempFolder)) {
-            if (!mkdir($tempFolder) && !is_dir($tempFolder)) {
-                throw new RuntimeException(sprintf('Directory "%s" was not created', $tempFolder));
-            }
+        if (!$this->isDirOrMkdir($tempFolder)) {
+            throw new RuntimeException(sprintf('Directory "%s" was not created', $tempFolder));
         }
 
         return $tempFolder;
diff --git a/tests/PhpSpreadsheetTests/Helper/SampleCoverageTest.php b/tests/PhpSpreadsheetTests/Helper/SampleCoverageTest.php
new file mode 100644
index 000000000..f3f616fe6
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Helper/SampleCoverageTest.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Helper;
+
+use PhpOffice\PhpSpreadsheet\Helper\Sample;
+use PHPUnit\Framework\TestCase;
+use RuntimeException;
+
+/**
+ * @covers \PhpOffice\PhpSpreadsheet\Helper\Sample
+ */
+class SampleCoverageTest extends TestCase
+{
+    public function testSample(): void
+    {
+        $helper = new Sample();
+        $samples = $helper->getSamples();
+        self::assertArrayHasKey('Basic', $samples);
+        $basic = $samples['Basic'];
+        self::assertArrayHasKey('02 Types', $basic);
+        self::assertSame('Basic/02_Types.php', $basic['02 Types']);
+        self::assertSame('phpunit', $helper->getPageTitle());
+        self::assertSame('<h1>phpunit</h1>', $helper->getPageHeading());
+    }
+
+    public function testDirectoryFail(): void
+    {
+        $this->expectException(RuntimeException::class);
+
+        $helper = $this->getMockBuilder(Sample::class)
+            ->onlyMethods(['isDirOrMkdir'])
+            ->getMock();
+        $helper->expects(self::once())
+            ->method('isDirOrMkdir')
+            ->with(self::isType('string'))
+            ->willReturn(false);
+        self::assertSame('', $helper->getFilename('a.xlsx'));
+    }
+}