How do you test fonts?

this is the question asked in the BBST course from AST, it really provokes your thinking, to rephrase the question – lets say you are developing a text application, how would you ensure it is displaying the fonts correctly?

my answer is:

first i will:

and ensure my application as shown in typeface document, and similar to competitor products

second:

third:

only if i am satisfied with above 2 levels:-

and ensure at step three the look is all same.