Touching would determine that it is a White paper and if you write with White Marker , you will not be able to read the text clearly

and writing with a white marker on a ceramic piece or whiteboard cut out to look like a paper would still make the text unreadable.

just by writing with white marker on that paper.

One test case to check if there is any 0.001 dot of color other than white,If a single dot is there other than white color its not white else its white

Write something with white marker on white paper.. it should not be visible..

Write "Hi" using Blue color ink. If the ink is Blue, then it is white else, it is not white. Reason: Original color reproduced only on white paper. Other colors won't reproduce original color.

Flag as InappropriateFlag as Inappropriate ▲ 0 ▼ and writing with a white marker on a ceramic piece or whiteboard cut out to look like a paper would still make the text unreadable. Anonymous on 11 Mar 2014 Flag as InappropriateFlag as Inappropriate ▲ 0 ▼ just by writing with white marker on that paper. Anonymous on 28 Jan 2016 Flag as InappropriateFlag as Inappropriate ▲ 1 ▼ One test case to check if there is any 0.001 dot of color other than white,If a single dot is there other than white color its not white else its white Roopa on 31 Aug 2018 Flag as InappropriateFlag as Inappropriate ▲ 0 ▼ Write something with white marker on white paper.. it should not be visible

The interviewer said just one effective test case. Writing with white marker is the 2nd testcase.