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%.

Find out more about structural coverage in our white paper.

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 can be run on the following x86-64 operating systems:

• Windows 10 and 11
• Windows Server 2019+
• 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.

While RapiCover has very low instrumentation overheads, it may not be possible to collect all coverage from the same build or run due to code size or timing-related constraints.

RapiCover lets you collect coverage incrementally from multiple builds, allowing you to generate full coverage reports efficiently, even on resource-constrained systems.

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 2021, we resolved 63% of our support requests within 7 working days and 93% within 30 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.

Yes, you can create and manage groups of users for your floating RVS licenses. You can restrict each group to only serve licenses to specific hostnames or IP addresses. This allows you to reserve licenses for specific groups or specific purposes such as supporting the use of RVS on a continuous integration server.

Any licenses that you don’t reserve will remain available as floating licenses that can be shared among different users and geographic locations.

Yes. RVS has an out-of-the-box integration with Deos, which makes it possible to generate an RVS project including a RapiCover integration in just 3 clicks from an existing OpenArbor project.

This benefits from the debug capabilities offered by Deos to automatically apply configuration settings needed for your project and RapiCover integration.

In addition to supporting on-target structural coverage analysis, the generated integration lets you perform on-target worst-case execution time analysis with RapiTime and visualize the scheduling behavior of your code with RapiTask.

RVS supports the analysis of shared code compiled by build systems with multiple executables by letting you specify the source files that will be compiled in each executable. 

If you have functions that are declared in multiple components with the same name but have different definitions, RVS can treat each such function uniquely, for example to provide separate coverage in RapiCover and separate execution time results in RapiTime.

RVS analyzes the structure of your code and presents information on your code’s structure, helping you understand your code and its dependencies in a variety of forms such as the following:

• RVS analyzes the McCabe complexity of your code and presents the complexity of each code element, letting you easily identify code with high complexity. 
• RVS Treemaps present the hierarchy of your code’s components and source files graphically.
• RVS lets you view and explore the call dependencies in your code.  

RVS can supplement model-based development workflows using MATLAB® Simulink® to support on-target verification of model-based code and verification of handwritten code.   

RapiCover supports generating structural coverage metrics for model-based code in SIL, PIL and HIL testing environments, while RapiTime supports execution time analysis including WCET analysis of model-based code from on-target testing in PIL and HIL environments.

RVS can be used to support functional testing, structural coverage analysis and execution time/WCET analysis of additional handwritten code used in projects that use Simulink.

Different variants of RapiCover are available, each of which is optimized to best meet the verification needs of specific software industries:

• RapiCover Aero includes example projects, tutorials and analysis profiles optimized for engineers working on DO-178C/ED-12C projects. Coverage analysis profiles are available based on verification requirements for DAL A-C software.
• RapiCover Auto includes example projects, tutorials and analysis profiles optimized for engineers working on ISO 26262 projects. Coverage analysis profiles are available based on verification requirements for ASIL A-D software.
• RapiCover Space includes example projects, tutorials and analysis profiles optimized for engineers working on NASA-STD-8739.8B and ECSS-E-ST-40C projects. For ECSS-E-ST-40C, coverage analysis profiles are available based on verification requirements for software Criticality Category.

RVS supports meeting standards and guidelines for verification of mission and safety-critical applications including:

• Civil aerospace software guidelines DO-178C (ED-12C), DO-278A (ED-109), AC 20-193 & AMC 20-193
• Military & defense aerospace standards MIL-HDBK-516C, AA-22-01 AMACC, EMACC, ADSM, Def Stan 00-55 & Def Stan 00-56
• Automotive standard ISO 26262
• Space software standards NASA-STD-8739.8B, ECSS-E-ST-40C
• Other standards based on IEC 61508, including IEC 62279, EN50128 & EN 50657 (rail), IEC 61511 (industrial processes), IEC 61513 (power), IEC 60880 (nuclear) & IEC 62061 (machinery)

No, but you can use RapiCover^Zero for your structural coverage analysis.

Both RapiCover and RapiCover^Zero support on-target structural coverage analysis for critical software. 

Depending on your project and needs, one or both solutions may be better for you. Consult the table below to determine which is best for your project.

RapiCover can help you meet DO-178C objective 6.4.4.c, which indicates that structural coverage analysis is performed on the software based on requirements-based tests of its behavior. RapiCover supports structural coverage analysis at the statement, decision, and Modified Condition/Decision Coverage levels, completing the evidence you need for the analysis.

RapiCover justifications help you with DO-178C “structural coverage resolution” by letting you mark coverage holes as justified or covered by analysis.

As RapiCover is designed to collect results from tests run on-target, it also helps you achieve DO-178C objective 6.4.e.

RapiCover (together with RapiCover Zero) can also support meeting the “additional code verification” part of DO-178C objective 6.4.4.c for DAL A software, which indicates that evidence is available for the correctness of additional code introduced by the compiler. 

For a detailed description of how RVS tools including RapiCover can help you achieve DO-178C certification, see our web page on how to achieve DO-178C certification.

RVS make it easy to get started with a range of resources:

• Interactive tutorials guide you through using each RVS tool.
• Example projects, reports and tests let you explore using RVS with example code, while sandbox projects let you plug in Ada, C and C++ snippets and get started with on-host verification quickly.
• If you’re looking for more detail about specific topics, the RVS documentation is at hand.  

And no matter what your question, RVS’s help search can link you to the most helpful resources at the click of a button.