Glass Box Testing

What is Glass Box Testing?

Glass box testing is a testing technique that examines the program structure and derives test data from the program logic/code. The other names of glass box testing are clear box testing, open box testing, logic driven testing or path driven testing or structural testing.

Glass Box Testing Techniques:

• Statement Coverage - This technique is aimed at exercising all programming statements with minimal tests.

• Branch Coverage - This technique is running a series of tests to ensure that all branches are tested at least once.

• Path Coverage - This technique corresponds to testing all possible paths which means that each statement and branch is covered.

Calculating Structural Testing Effectiveness:

Statement Testing = (Number of Statements Exercised / Total Number of Statements) x 100 %

Branch Testing = (Number of decisions outcomes tested / Total Number of decision Outcomes) x 100 %

Path Coverage = (Number paths exercised / Total Number of paths in the program) x 100 %

Advantages of Glass Box Testing:

• Forces test developer to reason carefully about implementation.

• Reveals errors in "hidden" code.

• Spots the Dead Code or other issues with respect to best programming practices.

Disadvantages of Glass Box Testing:

• Expensive as one has to spend both time and money to perform white box testing.

• Every possibility that few lines of code is missed accidentally.

• In-depth knowledge about the programming language is necessary to perform white box testing.