/**
  * @param $ex
  * @param $a
  * @param $b
  * @param $c
  * @dataProvider calcSquareFigureProvider
  */
 public function testCalcSquareFigure($ex, $a, $b, $c)
 {
     $tri = new Triangle();
     $tri->setA($a);
     $tri->setB($b);
     $tri->setC($c);
     $tri->calcPerimeterFigure();
     $this->assertEquals($ex, $tri->calcSquareFigure());
 }
    $tri->setB($_POST['b']);
} else {
    $tri->setB('');
}
if (isset($_POST['c'])) {
    $tri->setC($_POST['c']);
} else {
    $tri->setC('');
}
if (isset($_POST['function'])) {
    $function = $_POST['function'];
} else {
    $function = '';
}
$tri->calcPerimeterFigure();
$tri->calcSquareFigure();
?>

<div>
    <h3>Triangle</h3>
    <form method="post">
        <label for="a">Side A</label>
        <input type="text" name="a"><br>
        <label for="a">Side B</label>
        <input type="text" name="b"><br>
        <label for="a">Side C</label>
        <input type="text" name="c"><br>
        <select name="function">
            <option name="insert" value="insert">insert</option>
            <option name="remove" value="remove">remove</option>
            <option name="update" value="update">update</option>