On page 90, CalculateNAVTest.java
:
public class CalculateNAVTest {
@Test
public void computeStockWorth() {
final CalculateNAV calculateNAV = new CalculateNAV(ticker -> new BigDecimal("6.01"));
BigDecimal expected = new BigDecimal("6010.00");
assertEquals(0, calculateNAV.computeStockWorth("GOOG", 1000).compareTo(expected), 0.001);
}
The assertEquals()
makes no sense.
It runs BigDecimal.compare( new BigDecimal("6010") , new BigDecimal("6010.00") )
which is either -1, 0 or +1, and compares it with 0 with an irrelevant precision of 0.001.
What we want is:
public class CalculateNAVTest {
@Test
public void computeStockWorth() {
final CalculateNAV calculateNAV = new CalculateNAV(ticker -> new BigDecimal("6.01"));
BigDecimal expected = new BigDecimal("6010.00");
BigDecimal actual = calculateNAV.computeStockWorth("GOOG", 1000);
BigDecimal delta = actual.subtract(expected);
assertEquals(delta.doubleValue(), 0, 0.001);
}
JavaDoc for BigDecimal.compare():