public function testAddFieldToFilter() { $field = 'title'; $value = 'test_filter'; $searchSql = 'sql query'; $this->collection->expects($this->once())->method('_translateCondition')->with($field, $value)->will($this->returnValue($searchSql)); $this->select->expects($this->once())->method('where')->with($this->equalTo($searchSql), $this->equalTo(null), $this->equalTo(\Magento\Framework\DB\Select::TYPE_CONDITION)); $this->collection->addFieldToFilter($field, $value); }