{{Unreferenced, date=November 2022 Fault coverage refers to the percentage of some type of fault that can be detected during the test of any engineered system. High fault coverage is particularly valuable during manufacturing test, and techniques such as

Design For Test Design for testing or design for testability (DFT) consists of IC design techniques that add testability features to a hardware product design. The added features make it easier to develop and apply manufacturing tests to the designed hardware. Th ...

(DFT) and

automatic test pattern generation ATPG (acronym for both Automatic Test Pattern Generation and Automatic Test Pattern Generator) is an electronic design automation method/technology used to find an input (or test) sequence that, when applied to a digital circuit, enables automatic t ...

are used to increase it. In

electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...

for example, stuck-at fault coverage is measured by sticking each pin of the hardware model at logic '0' and logic '1', respectively, and running the test vectors. If at least one of the outputs differs from what is to be expected, the fault is said to be detected. Conceptually, the total number of simulation runs is twice the number of pins (since each pin is stuck in one of two ways, and both faults should be detected). However, there are many optimizations that can reduce the needed computation. In particular, often many non-interacting faults can be simulated in one run, and each simulation can be terminated as soon as a fault is detected. A fault coverage test passes when at least a specified percentage of all possible faults can be detected. If it does not pass, at least three options are possible. First, the designer can augment or otherwise improve the vector set, perhaps by using a more effective

tool. Second, the circuit may be re-defined for better fault detectibility (improved controllability and observability). Third, the designer may simply accept the lower coverage.

Test coverage (computing)

The term test coverage used in the context of programming / software engineering, refers to measuring how much a software program has been exercised by tests. Coverage is a means of determining the rigour with which the question underlying the test has been answered. There are many kinds of test coverage: *

code coverage In computer science, test coverage is a percentage measure of the degree to which the source code of a program is executed when a particular test suite is run. A program with high test coverage has more of its source code executed during testing, ...

* feature coverage, * scenario coverage, * screen item coverage * model coverage. Each of these coverage types assumes that some kind of baseline exists which defines the system under test. The number of types of test coverage therefore varies as the number of ways of defining the system. For example, in

: * has a particular statement ever been executed? * how many times has a statement been executed? * have all the statements in a program been executed, at least once? * have all the decision points in the code been exercised such that every decision path has been taken? * has the last optimization reduced the

instruction path length In computer performance, the instruction path length is the number of machine code instructions required to execute a section of a computer program. The total path length for the entire program could be deemed a measure of the algorithm's performa ...

significantly?

External links

gate-level fault simulator PROOFS for non-profit educational institutions from the University of Illinois

Electronic design Electronic design automation Electronic engineering Integrated circuits

Test coverage (computing)

See also

External links