Software Development

Test coverage using testing tools and methods


To define “Test coverage” we have to talk about the topics stated below:

  1. The purpose of test coverage.
  2. Different types of test coverage standards.
  3. Test coverage metrics
  4. Unit test coverage
  5. Test coverage tools
  6. Advantage and disadvantage of test coverage.

The purpose of test coverage

Test coverage is an estimate utilized in software testing. It gives details about the level to which the written coding of an application has been tested.

It is a type of testing that seems straight and so appears in the caption of white box testing. Presently, the importance of test coverage is extensive in the ground of software engineering, the current plan method of which depends on computer languages. Test coverage methods are among the initial methods discovered for efficient software testing.

Different types of test coverage standards.

To calculate what proportion of code has been covered by a test collection, one or more coverage standards are utilized. These standards are generally distinct as a regulation or necessity.

Essential coverage standard

There is lots of coverage standards, the importance are as follows

  • Function coverage – Here every process or functions in the system has been recognized.
  • Statement coverage – Every statement in the system been executed.
  • Branch coverage – Every division of every system configuration been executed.
  • Condition coverage – Every Boolean sub phrase calculated both to correct and incorrect.

Customized conclusion coverage

It is amalgamation of function coverage and branch coverage and occasionally also describe conclusion coverage. This standard needs that each position of access and depart in the application have been called up as a minimum one time, and each conclusion in the application have employed all probable results as a minimum one time. Here in this situation the conclusion is a Boolean term collected of situation and none or added Boolean operatives. This description is not the similar like branch coverage, though; various employ the word conclusion coverage as another word for branch coverage.

Conclusion coverage needs that equally conclusion and situation coverage been pleased. Though, for security vital program it is frequently necessary that customized conclusion coverage be fulfilled. This standard expands conclusion standard with necessities that every state must influence the conclusion.

Various state coverage

This standard needs that all amalgamation of situations within every conclusion is experienced.

Constraint value coverage

Constraint value coverage needs that in a process taking constraints, the entire general principles for those constraints been measured. The initiative is that all general probable principles for a constraint are experienced.

Unit Test Coverage

Unit tests notify us if the source code executed as estimated, and test coverage notifies us what lefts to be tested.

Mainly programmers recognize this method and consent on its value proposal, and frequently objective full coverage. Though full coverage is an excellent aim, full of the incorrect sort of treatment may direct to troubles. A distinctive software creation attempt procedures treatment in words of the amount of any statement or branches to be tested. Yet with full statement or branch coverage, serious errors might be there in the logic of the source code, avoiding both programmers and administrators with a fake logic of protection.

Statement and branch coverage are good for discovering obvious troubles established in unimplemented source code, but frequently overlook errors linked to equally conclusion configurations and conclusion connections. On the additional, path coverage is a stronger and inclusive procedure that assists discloses imperfection early on.

Test coverage metrics

There are six kinds of test coverage metrics, which are describes below.

Line Coverage

Line coverage check is the line of source code implemented at the time of replication. Enclosed will demonstrate the amount of reasonable lines of source code that present in a appropriate file with the amount of reasonable lines that were implemented at the time of the replication alongside with a proportion representative the proportion of lines implemented. If wordy form is chosen for a statement, enclosed will demonstrate the lines of reason that were not implemented throughout the replication execution.

Toggle Coverage

Toggle coverage checks at the time of replication are this bit of the line or catalog transform from a significance of zero to one and get back from one to zero. A bit is supposed to be completely enclosed when it closures rear and onward as a minimum one time. This metric does not signify to the end user that each worth of a multi-bit vector was observed.

Memory Coverage

Memory coverage checks an amount of issues regarding recollections or multidimensional collections being employed in the design, together with the following details:

Checks all bits of every accessible remembrance component closure from 0 to 1.

  • Checks all bits of every accessible remembrance component closure from 1 to 0.
  • Checks every accessible remembrance component can be written down.
  • Checks every accessible remembrance component can be comprehend.

Recollections or multidimensional collections might have two kinds of extents, those are packed and unpacked. Packed aspects details are particular to the left of a collection statement though unpacked aspects details are particular to the right of a collection statement.

Combinational Logic Coverage

This type of coverage checks the results when a functions estimates to throughout the lessons of the recreation.

This kind of combination logic coverage is awfully valuable in formative rational amalgamations of indications that were not attempted at the time of recreation, revealing probable gaps in confirmation.

Finite State Machine Coverage

This sort of coverage metrics checks if it is possible to achieve each of the conditions and go across every probable pathway throughout a specified state machine.

Finite state machine coverage has two types of coverage details which are enclosed can handle,

  • Condition coverage – It checks all condition of finite state machine coverage hits at the time of recreation.
  • Condition evolution coverage – It checks the finite state machine coverage evolution among all condition in recreation.

Assertion Coverage

This type of coverage metrics checks all of the probable coverage issues of the declaration which is incorporated in the design can be hit.

Presently, enclosed is able of discovery all open confirmation language statement components observed in the plan. In the majority open confirmation language declaration components are one or more integral coverage issues. While the end user has precise an exacting declaration example to ensure for an exposure reason, enclosed replicates this declaration component, maintenance follow of which treatment issues in the declaration have been hit through recreation and which have not. This permits the end user to ensure for additional composite treatment situations in the plan.

At present, only open verification language edition 1.6 and new is maintained. Previous editions of the open verification language might not work and are not intended to be maintained.

Test coverage tools

Code coverage Tools

Presently the programmer group of people is in a comparatively fine condition concerning the accessibility of high class test coverage tools. We are going to take a glance at a small amount of, but there are plenty more out there, the majorities are for trade, but various are complimentary or yet open source.

Preliminary, we begin by observing how test coverage dealings are normally executed.

Execution method

The executions method may be classified into two separate execution types:

  • Instrumentation

This type method is concerning influencing the source code by inserting coverage code into planned locations. In details, the way of instrumentation has two instructs: class instrumentation and source instrumentation. Not unexpectedly, the differentiation is that class instrumentation inserts the coverage code straightly into assembles .class files whereas source instrumentation generates a mediator edition of the resources which are then assembled into the ultimate, source implemented .class files. Nearly all test coverage tools have selected one of these two instrumentation methods.

  • Custom JVM

One more option to inserting coverage code to the byte code is to shift that liability into the custom JVM itself. Test coverage investigation might be executed by having the fundamental instrument continue calculation of which division of the overloaded classes are carry out. In observe, though, there isn’t any accepted tools taking this type.

Advantage and disadvantage of test coverage


  • It builds extra test conditions to enhance exposure.
  • It assists in discovering location of a application not implemented by a group of test conditions.
  • It assists influentially a significant calculation of test coverage, which ultimately procedures the excellence of the software application.


  • One problem of test coverage capacity is that it calculates treatment of what has been written down, that is the code can’t declare anything regarding the application that has not been written down.
  • If a particular method has not been executed or a method was deleted from the requirement, then configuration basis methods can’t declare anything about them it simply observes at a configuration which is previously present.


Employing several kind of test coverage method is a phase in the accurate track so far it is simple to misunderstand the outcomes. Though statement and branch coverage metrics are simple to calculate and accomplish together may depart serious faults unexposed, providing programmers and administrators a fake intelligence of defense. Foundation path coverage gives an additional healthy and complete way for discovering these overlooked faults lacking aggressively growing the amount of tests essential.


Kaushik Pal

Kaushik has 16 years of experience as a technical architect and software consultant in enterprise application and product development. He has interest in new technology and innovation area along with technical writing. His main focus is on web architecture, web technologies, java/j2ee, Open source, big data and semantic technologies. He has demonstrated his expertise in requirement analysis, architecture design & implementation, technical use case preparation, and software development. His experience has spanned in different domains like Insurance, banking, airlines, shipping, document management etc. Kaushik worked with a wide variety of technologies starting from Mainframe (IBM S/390), midrange (AS/400), web technologies and open source area. He has worked with clients like IBM, Lexmark, United Airlines and many more.
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