@Test
    public void testDot() {
        Assert.assertEquals(16, parse("4*4"), 0.00001);
        Assert.assertEquals(5, parse("4*5/4"), 0.00001);
    }

    @Test
    public void testDash() {
        Assert.assertEquals(8, parse("4+4"), 0.00001);
        Assert.assertEquals(5, parse("5-1+2-1"), 0.00001);
    }

    @Test
    public void testDotBeforeDash() {
        Assert.assertEquals(7, parse("1+2*3"), 0.00001);
        Assert.assertEquals(11, parse("1+2*3+4"), 0.00001);
        Assert.assertEquals(7, parse("2*3+1"), 0.00001);
    }

    @Test
    public void testBrackets() {
        Assert.assertEquals(7, parse("(7)"), 0.00001);
        Assert.assertEquals(7, parse("(3+4)"), 0.00001);
        Assert.assertEquals(14, parse("(3+4)*2"), 0.00001);
        Assert.assertEquals(3.5, parse("(3+4)/2"), 0.00001);
        Assert.assertEquals(6, parse("(3*4)/2"), 0.00001);
        Assert.assertEquals(8, parse("4*(5-3)"), 0.00001);
    }

    @Test
    public void testVariables() {
        Assert.assertEquals(10, parse("y=5 y*2"), 0.00001);
        Assert.assertEquals(0, parse("y = 2 z = 5 x = y + ( 3 - z )"), 0.00001);
        Assert.assertEquals(3, parse("x = y + ( 3 - z ) "), 0.00001);
        Assert.assertEquals(10, parse("ahsd=5 2 * ahsd"), 0.00001);
    }

    public void testWhiteSpace() {
        Assert.assertEquals(10, parse("y       = \n \t 5 * 4 + 5"), 0.00001);
    }

    @Test
    public void testError() {
        try {
            parse("()");
            Assert.fail("Empty brackets");
        } catch (Exception e) {
        }

        try {
            parse("2*");
            Assert.fail("missing operand at end");
        } catch (Exception e) {
        }

        try {
            parse("*2");
            Assert.fail("missing operand at begin");
        } catch (Exception e) {
        }

        try {
            parse("(*2)");
            Assert.fail("missing operand with brackets");
        } catch (Exception e) {
        }

        try {
            parse("*2+4*3");
            Assert.fail("missing operand at begin - more complex");
        } catch (Exception e) {
        }
    }