Testing manual entry
New Flight f1 entered:AA123 from BOS to LAX 

Testing constructor
New Flight f2 created:DL55 from LAX to SFO 

Testing constructor
New Flight f3 created:OA1234 from SFO to ATH 

Testing getAirline(f1):(AA)->: AA

Testing getFlightNumber(f1):(123)->: 123

Testing getOrigin(f1):(BOS)->: BOS

Testing getDestination(f1):(LAX)->: LAX

Flights AA123 from BOS to LAX  and DL55 from LAX to SFO  share stopover city (TRUE)->: true

Flights DL55 from LAX to SFO  and AA123 from BOS to LAX  share stopover city (FALS)->: false

Flights DL55 from LAX to SFO  and OA1234 from SFO to ATH  share stopover city (TRUE->): true

Testing setDestination(f1):BOS

Testing setOrigin(f1):SFO

Testing changes to Flight f1:AA123 from SFO to BOS
 
Flights AA123 from SFO to BOS  and DL55 from LAX to SFO  share stopover city (FALSE)->: false

Flights DL55 from LAX to SFO  and AA123 from SFO to BOS  share stopover city (TRUE)->: true