Test Case Discussion

• The boundary values for this problem are 90, 80, 70, and 60.
• These are the values where the output changes from one letter grade to another.
• Notice that the test plan tests the boundaries with test cases right at the boundary and also with test cases just above and just below the boundary values.

• The "branches" for this problem are each of the letter grades.
  
• The branch cases are the ones that test each letter grade with a value that is not a bounds test, for instance 95.0.
• Your test plan should have at least one branch test for each branch, in this case one for each letter grade.

• The error test is -92.0.
• We can consider it an error test case because it is unexpected input.
• It is important that we think about input like this and make sure our algorithm handles it in a reasonable way.
• According to our test plan we will handle negative values as F, but we could decide to handle it as something else, such as ?.

• What about the 103.64 test case? Is it a definitely a branch test?
• The answer to that question depends on your analysis of the problem.
• Is it possible to have a score over 100%? If so, then it is a branch test and is testing an A that is more that 100%.
• If it was impossible to have a score over 100%, the we should consider it an error case.
• In that case, the output should NOT be an A.
• You may decide to have a cutoff for the upper value that is an A, for instance 110%.
• If so, then 110 is another boundary for you to test and you would need to add another error test, one that is more than 110%.