/**
  * @covers ::getCacheTags
  */
 public function testGetCacheTags()
 {
     $module_handler = $this->prophesize(ModuleHandlerInterface::class);
     $plugin_manager = new TestPluginManager($this->namespaces, $this->expectedDefinitions, $module_handler->reveal(), NULL);
     $cache_tags = $plugin_manager->getCacheTags();
     $this->assertInternalType('array', $cache_tags);
     array_map(function ($cache_tag) {
         $this->assertInternalType('string', $cache_tag);
     }, $cache_tags);
 }