Design For Testability

Question 1

code that is easy to test..

Answer 1

is code that is well designed

Question 2

what is testability

Answer 2

a non functional requirement

easy to test

Question 3

what is design for testability

Answer 3

testability concerns drive the design

Question 4

what are difficulties in design for testability.

Answer 4

non deterministic code

hard coded/hidden behaviour

not allowing inheritance/override

complex/slow configurations

breaking the law of demeter

Question 5

what is the law of demeter

Answer 5

principle of least knowledge

only limited knowledge about other units:
Only talk to immediate friends.

Question 6

what is a test double

Answer 6

version of code object whose behaviour is predictable and controllable

Question 7

describe a dummy

Answer 7

passed around but never used

Question 8

describe a stub

Answer 8

provide canned answers to calls

Question 9

describe fakes

Answer 9

have implementations but take short cuts

Question 10

describe mocks

Answer 10

created on the fly

behaviour matches programmed expectations.

fixed return values

can verify behaviour, such as number of calls

Question 11

what is design for testibility

Answer 11

allows us to predict behaviour and plan for it from the start. All classes have at least two clients from the start.