public void ToStringTest()
{
String s1 = "CO2 + H2O = C6H12O6 + O2";
ChemEqnMatrix cm = new ChemEqnMatrix(s1);
string result = cm.ToString();
string expected = "1 0 -6 0 0 2 1 -6 -2 0 0 2 -12 0 0 1 0 0 0 1 ";
Assert.AreEqual(expected, result);
}