--- /dev/null
+<?php
+
+namespace Drupal\Tests\comment\Unit;
+
+use Drupal\comment\CommentStatistics;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\comment\CommentStatistics
+ * @group comment
+ */
+class CommentStatisticsUnitTest extends UnitTestCase {
+
+ /**
+ * Mock statement.
+ *
+ * @var \Drupal\Core\Database\Statement
+ */
+ protected $statement;
+
+ /**
+ * Mock select interface.
+ *
+ * @var \Drupal\Core\Database\Query\SelectInterface
+ */
+ protected $select;
+
+ /**
+ * Mock database connection.
+ *
+ * @var \Drupal\Core\Database\Connection
+ */
+ protected $database;
+
+ /**
+ * CommentStatistics service under test.
+ *
+ * @var \Drupal\comment\CommentStatisticsInterface
+ */
+ protected $commentStatistics;
+
+ /**
+ * Counts calls to fetchAssoc().
+ *
+ * @var int
+ */
+ protected $calls_to_fetch;
+
+ /**
+ * Sets up required mocks and the CommentStatistics service under test.
+ */
+ protected function setUp() {
+ $this->statement = $this->getMockBuilder('Drupal\Core\Database\Driver\sqlite\Statement')
+ ->disableOriginalConstructor()
+ ->getMock();
+
+ $this->statement->expects($this->any())
+ ->method('fetchObject')
+ ->will($this->returnCallback([$this, 'fetchObjectCallback']));
+
+ $this->select = $this->getMockBuilder('Drupal\Core\Database\Query\Select')
+ ->disableOriginalConstructor()
+ ->getMock();
+
+ $this->select->expects($this->any())
+ ->method('fields')
+ ->will($this->returnSelf());
+
+ $this->select->expects($this->any())
+ ->method('condition')
+ ->will($this->returnSelf());
+
+ $this->select->expects($this->any())
+ ->method('execute')
+ ->will($this->returnValue($this->statement));
+
+ $this->database = $this->getMockBuilder('Drupal\Core\Database\Connection')
+ ->disableOriginalConstructor()
+ ->getMock();
+
+ $this->database->expects($this->once())
+ ->method('select')
+ ->will($this->returnValue($this->select));
+
+ $this->commentStatistics = new CommentStatistics($this->database, $this->getMock('Drupal\Core\Session\AccountInterface'), $this->getMock('Drupal\Core\Entity\EntityManagerInterface'), $this->getMock('Drupal\Core\State\StateInterface'));
+ }
+
+ /**
+ * Tests the read method.
+ *
+ * @see \Drupal\comment\CommentStatistics::read()
+ *
+ * @group Drupal
+ * @group Comment
+ */
+ public function testRead() {
+ $this->calls_to_fetch = 0;
+ $results = $this->commentStatistics->read(['1' => 'boo', '2' => 'foo'], 'snafoos');
+ $this->assertEquals($results, ['something', 'something-else']);
+ }
+
+ /**
+ * Return value callback for fetchObject() function on mocked object.
+ *
+ * @return bool|string
+ * 'Something' on first, 'something-else' on second and FALSE for the
+ * other calls to function.
+ */
+ public function fetchObjectCallback() {
+ $this->calls_to_fetch++;
+ switch ($this->calls_to_fetch) {
+ case 1:
+ return 'something';
+
+ case 2:
+ return 'something-else';
+
+ default:
+ return FALSE;
+ }
+ }
+
+}