Decision coverage and branch coverage are closely-related forms of structural coverage analysis. Decision coverage is referenced by DO-178B/DO-178C whereas branch coverage is referenced by ISO 26262. Branch coverage requires every exit from a conditional source code statement to be executed. Thus, for an if statement, branch coverage requires the then part and the else part to be executed (if there is no else part, the if statement should still execute the decision as true and false). For decision coverage, the DO-178B/DO-178C definition of decision covers conditional statements, in the same way as branch coverage, but it also includes assignments of Boolean variables, for example:

a := b or (c and d); (Ada)
a = b || (c && d); (C/C++)

In this case, decision coverage would require tests for the above assignment making a both true and false.

Moreover, given the same source code and tests to exercise it, the percentage of coverage reported may be different between branch and decision coverage. For example, if 3 out of the 4 branches of a switch statement are executed, the branch coverage would be reported as 75%, but for decision coverage, a decision is considered covered only if all its branches are covered, so the coverage of the switch statement would be reported as 0%.

You can request a trial version of RVS, which includes RapiCover. You can also arrange a demonstration, where a member of our team will work with you to show the benefits RapiCover can offer you.

If you're interested in RapiCover in academia, you can search for it in the academic press. 

RapiCover is the leading tool for structural code coverage analysis of critical software.

Used globally in the aerospace and automotive industries, it reduces the cost of analyzing structural code coverage analysis up to and including MC/DC.

As part of the RVS toolsuite, it forms part of a software verification solution that also includes tools for functional testing and worst-case execution time analysis. 

RapiCover works by injecting instrumentation code into source code and executing the native build system so that coverage results are collected during program execution. Data can be collected from almost any target hardware by a variety of approaches.

RVS tools support Windows 7 or newer, Windows Server 2008 R2 or newer, and a variety of Linux distributions including Ubuntu and Red Hat.

RVS tools can be used on projects with unsupported operating systems by using a clone integration to split the process and delegate parts of it to the unsupported machine.

RVS tools can be integrated to work with almost any embedded target. Our engineers can work with you to determine the optimal strategy for integrating the tool with your target, even for multi-core architectures. For more information on the hardware architectures we have integrated RVS tools with, see the compatibility information on our RVS product pages.

RapiCover can be integrated to work with almost any compiler and target hardware. Our integration service promises to deliver a robust integration of RapiCover into your build system.

RapiCover supports C, C++ and Ada projects, including mixed-language ones.

RapiCover is designed to meet the most stringent needs of certification processes, such as the DO-178B/C process used in the aerospace industry and the ISO 26262 process used in the automotive industry. We can provide developer qualification documents, a template integration qualification report and on-site tests to support you in qualifying RapiCover tools in projects requiring certification.

RapiCover can be configured to collect data in real-time while your software runs. By writing data to an external device, the data will remain in place while your system reboots, and collection can be reinitialized when it restarts. This means that you can collect coverage data across a shutdown or reset sequence. This is subject to your target hardware architecture. 

By default, RapiCover supports 30 conditions per decision, and includes support for up to 1000 conditions per decision using an alternate, inbuilt instrumentation strategy.

Using our configurable instrumentation mechanism, you can instruct RapiCover to determine coverage for specific subprograms as necessary. After running your tests, it’s easy to merge coverage data from these runs into a combined report using RapiCover’s Merge Coverage utility.

You can measure the most common coverage criteria required to support DO-178B/ED-12B, DO-178C/ED-12C and ISO 26262 certification using RapiCover. This includes function, call, statement, branch, decision and condition coverage, and MC/DC.

RVS tools are designed to handle very large code bases. Because of the efficient algorithms used by RVS tools, there is no fundamental limitation to the number of lines of code that RVS can process, and our RVS tools have been used on projects with millions of lines of code.

We offer both “Node-locked” and “Floating” licenses, and a license server to support use of our tools in your specific development environment. 

For more information on our licensing models, see our RVS licensing FAQs.

All RVS licenses include access to our dedicated in-house support team, who will work with you to provide a rapid fix to your issue. This is a critical part of our vision. During 2016, we responded to 97% of new support requests within one working day, closed 56% of these within 3 working days and 91% within 20 working days. We also inform our customers of known issues via our website and email. 

We provide an extensive set of RVS documentation with each of our products, and offer training courses guiding you through the most effective use of RVS tools. All our users can benefit from privileged access to our website, which includes downloads for new product releases. 

RapiCover and RapiCover^Zero include a powerful “justification” mechanism that lets you mark code as covered. Using this feature, you can provide a rationale for justifying the code and create templates to justify code more easily. When your code changes, justifications are automatically migrated to represent the new location of your justified code.

For more information on using justifications, see our white paper.

RapiCover and RapiCover^Zero retain information about the revision of your code it used to generate results. The tool will report an error if you try to merge coverage from incompatible revisions. RapiCover includes an Optimal Dataset Calculator feature you can use to calculate the least expensive tests you need to run again when your code changes, saving you valuable testing effort.

All RVS tools include a friendly user-interface that presents your results in both tabular and graphical formats. Using this interface, you can filter your results to zoom in on target functions, making it easy to find the information you are looking for.

Treemaps provide a high-level overview of your code base and help you understand the coverage of your code at a glance.

You can view RapiCover and RapiCover^Zero results in continuous integration software, allowing you to track your verification progress over time. 

RVS integrates with a range of continuous integration tools, allowing you to collect unit test, coverage and execution time results with every new build, track your verification progress over time and easily identify anomalies in your software's behavior as they are introduced.

RapiTest, RapiCover and RapiTime (including zero-footprint versions) include custom plugins to integrate with Jenkins and Bamboo. RapiTest and RapiCover results can also be displayed in a range of other continuous integration tools through the JUnit and Cobertura plugins, which are compatible with most continuous integration software. 

We recommend that, when performing functional testing of safety-critical applications for a final run-for-score, you run your full test suite both with and without coverage instrumentation applied, then confirm that the results match. This provides evidence that RVS instrumentation has not changed the functional behavior of your code.

The Rapita Verification Suite (RVS) has been used in the critical embedded industry for over 15 years and supported a number of avionics projects globally. Qualification kits for qualified RVS products have supported more than 20 DO-178B and C certification projects up to and including DAL A.

Yes, you do not need to use RapiTest to collect coverage results. RapiCover can instrument your test code so coverage results can be automatically collected as your tests as run, then displayed for analysis.

To support verification, RVS stores a copy of your source code in your verification results. RVS lets you remove this copy of your source code from your RVS project, so any subcontracting organizations you’re working with can’t see your proprietary information. A subcontracting organization can then verify aspects of your software using the redacted results, and you can later restore the copy of your source code for your internal use by merging your results.

Note that, as running functional tests requires access to the source code under test, this feature is not available for RapiTest.

Floating RVS licenses follow an “Enterprise” model. You can use them across geographical boundaries*, in different projects, with different users, and share them with suppliers working on the same project.

^*Some floating licenses may be restricted to use within a specific geographical region. Where this is the case, this is agreed before licenses are issued.