Delegating Requirement Coverage

Consider a situation where you are responsible for the high-level software architecture of your project. You define the component breakdown, the interfaces and the interworking of the components. You get your requirements from a system requirement specification, but it turns out many of those incoming requirements are at a detail level that does not require design decisions on inter-component-level but rather affects the internals of a single component.

In those cases it would be a waste of time to repeat the original requirement in your architecture just to hand them down to the detailed design of a component. Instead, what you need is a fast way to express “yes, I read that requirement, and I am sure it does not need design decisions in the high-level architecture.”

To achieve this, OFT features a shorthand notation for delegating the job of covering a specification item to one or more different artifact types.

In the following example, a requirement in the system requirement specification (artifact type req) stated that the web user interface of your product should use the corporate design. This clearly does not require an architectural decision (arch), so you forward it directly to the detailed design (dsn) level.

arch --> dsn : req~web-ui-uses-corporate-design~1

Please note that the arrow is intentionally done with two dashes (-->) in order to reduce the chance for parsing collisions since the arrow with one dash often appears in documents.

This notation can appear after:

  • A title
  • “Needs” section
  • “Depends” section
  • “Covers” section
  • “Tags” section

If it appears in a multi-line text section of a requirement (description, comment or rationale) the forward is ignored.

Note that a forward terminates the previous specification item, so the following notation does not work:

`dsn~foo~1`
…
Covers: req~foo~1

dsn-->impl:req~bar~1              <-- this terminates the previous specification item

Needs: impl,utest                 <-- this is now lost

To avoid confusion, it is best to have all forwards in a separate section with their own title:

# Forwarded Requirements

* `dsn-->impl:req~bar~1`
* `dsn-->impl:req~zoo~2`
* `…`

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