Add test for National Call
Add test for 1 minute National Call
Add test for 10 minutes NationalCall, passes
Add test for international calls
Some refactoring
Add test for international call to SA
Add test for 1 minute internationa call to NA
test passes
Add test for 1 minute call to NA
test passes
Add test for 1 minute international call to europe
Add test for 1 minute international call to Asia
Add test for basic fee in phone bill
Add test for local calls cost
Add test for non local calls costs.