CTAL-TTA Exam Dumps : Certified Tester Advanced Level Technical Test Analyst

Program tax check

Integer: tax_rate

real: tax%

BEGIN

tax% := 0

GET (tax_rate)

WHILE tax_rate > 0 loop

IF tax_rate > 3 THEN

tax_rate := 3

ENDIF

tax% := tax% + (tax_rate / 10)

tax_rate := tax_rate - 1

ENDLOOP

IF tax% > 0.6 THEN

print ("tax rate is high")

ELSEIF tax% < 0.1 THEN

print ("tax rate is zero")

ELSE

print ("tax rate is low")

ENDIF

END tax check

Explanation of Control Flow:

Initialization:

tax% := 0

Get Tax Rate:

GET (tax_rate)

While Loop:

Loop runs while tax_rate > 0.

Inside the loop:

If tax_rate > 3, set tax_rate to 3.

Update tax% by adding tax_rate / 10.

Decrement tax_rate by 1.

Post-Loop Condition Checks:

After the loop, check the value of tax%:

If tax% > 0.6, print "tax rate is high".

Else if tax% < 0.1, print "tax rate is zero".

Otherwise, print "tax rate is low".

Unreachable Code Analysis:

The ELSEIF tax% < 0.1 THEN condition (line 17) is unreachable.

In the loop, tax% is incremented by a minimum of 0.1 each time tax_rate is greater than 0.

Therefore, tax% cannot be less than 0.1 after the loop.

Conclusion:

Line 17 (ELSEIF tax% < 0.1 THEN) will never be true given the logic of the loop.

In the context of software testing, different safety integrity levels (SIL) require different levels of rigor in testing. According to the IEC61508 standard, for software components rated at SIL 2, achieving 100% statement coverage and 100% decision coverage is recommended. Statement coverage ensures that every line of code is executed at least once during testing, while decision coverage ensures that every decision in the code (e.g., every branch of an IF statement) is executed on both the true and false sides. These coverage criteria ensure a thorough testing of the software components to validate that they behave correctly in all circumstances. Multiple condition coverage and MC/DC coverage (Options A and B) are more rigorous and typically required for higher SIL levels, such as SIL 4.

The mnemonic FIRST is used to describe qualities of good unit tests in software development. Here, each letter stands for a critical attribute:

Fast: Tests should be quick to run.

Isolated: Tests should not depend on each other.

Reliable: Tests should consistently return the same results.

Self-Verifying: Tests should fully check their own results.

Timely: Tests should be written in a timely manner relative to the writing of the tested code. This mnemonic helps ensure that unit tests are effective and contribute positively to the development process .