private void btmRecArea_Click(object sender, EventArgs e)
{
int a = Convert.ToInt32(txtRecHeight.Text);
int b = Convert.ToInt32(txtRecWidth.Text);
lblRecArea.Text = Rectangle.RectArea(a, b).ToString("0.##");
}
public void RectAreaTest2()
{
RectangleArea rectangle = new RectangleArea();
int x = 4;
int y = 3;
int expectedValue = 20;
int actualValue = rectangle.RectArea(x, y);
Assert.AreNotEqual(expectedValue, actualValue);
}