### Question:
AwsRdsDbSubnetGroupView { public String getDBSubnetGroupName() { return databaseServer.getServerId() != null ? "dsg-" + databaseServer.getServerId() : null; } AwsRdsDbSubnetGroupView(DatabaseServer databaseServer); String getDBSubnetGroupName();  }### Answer:
@Test public void testDBSubnetGroupName() { when(server.getServerId()).thenReturn("myserver"); assertEquals("dsg-myserver", underTest.getDBSubnetGroupName()); }
@Test public void testNoDBSubnetGroupName() { when(server.getServerId()).thenReturn(null); assertNull(underTest.getDBSubnetGroupName()); }