Unit tests failing

Hi,

While lecture video shows unit tests passing, in my case running units tests is full of failures.

For eg, running MongoClientLesson.MongoCollectionInstance gives following error:

java.lang.AssertionError:
Expected :20
Actual :0

at org.junit.Assert.fail(Assert.java:88)
at org.junit.Assert.failNotEquals(Assert.java:834)
at org.junit.Assert.assertEquals(Assert.java:645)
at org.junit.Assert.assertEquals(Assert.java:631)