Example of Condition coverage

Simple example

Assume we want to test the following code extract:

if ( (A || B) && C )
{
/* instructions */
}
else
{
/* instructions */
}

where A, B and C represent atomic boolean expressions (i.e. not divisible in other boolean sub-expressions).

In order to ensure Condition coverage criteria for this example, A, B and C should be evaluated at least one time "true" and one time "false" during testes.

So, in our example, the 3 following testes would be sufficient to valid Condition coverage:

1. A = true  / B = not eval / C = false
2. A = false / B = true       / C = true
3. A = false / B = false      / C = not eval

More complex example

Assume we replace the condition: ( (A || B) && C )
by: ( ((u == 0) || (x>5)) && ((y<6) or (z == 0)) )

A full Test Coverage would consist into building the following truth table and testing each combination:

On the other hand, to ensure Condition coverage, we should test (for example) just the 3 combinations here-before underlined in yellow.

Go back to Test Coverage Levels

Glossary:

Condition: a logical indivisible (atomic) expression. It is often called boolean variable, represented by a capital letter (A, B, C, etc.), can only be equal to "true" or "false", but can not be divided in other simpler "sub-conditions".

Decision : a logical expression which can be composed of several conditions separated by logical operators like "or", "and", "xor".

The Test Coverage Analyzer Testwell CTC++ can do measurements for all kinds of test coverage criteria (particularly for MC/DC and MCC) requested for "critical software development" in order to get certifications, such as DO-178B of the Federal Aviation Administration (FAA).

last updated: 03.08.2010

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Author: Christophe Sourisse, Verifysoft Technology GmbH
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