Requirements
============
Use Cases
---------
.. requirement:definition:: UseCases.Build_Traceable_Documentation

:Description: As a safety engineer I want to build HTML documentation from
requirements, architecture diagrams, and safety analyses so that
all artefacts are rendered in a single navigable document with
cross-references and traceability information.

.. requirement:definition:: UseCases.Validate_Requirement_Chains

:Description: As a requirements engineer I want the build system to validate
that all component requirements trace back to feature requirements
and all feature requirements trace back to assumed system
requirements so that incomplete traceability is detected early.

.. requirement:definition:: UseCases.Render_Safety_Analyses

:Description: As a safety engineer I want FMEA failure modes and control
measures to be rendered into the documentation automatically so
that the safety analysis artefacts are always up to date with the
source TRLC definitions.

.. requirement:definition:: UseCases.Assemble_Dependable_Element

:Description: As a project lead I want to assemble a dependable element (SEooC)
from its components, requirements, architectural design and safety
analyses so that the complete safety case is represented as a
single auditable artefact.

.. requirement:definition:: UseCases.Parse_Architectural_Diagrams

:Description: As a software architect I want PlantUML component and sequence
diagrams to be parsed and verified during the build so that
architectural design errors are caught before integration.

.. requirement:definition:: UseCases.Verify_Architecture_Conformance

:Description: As a software architect I want the implemented component and unit
structure to be checked against the static architecture diagrams
during the build so that the delivered code does not drift away
from the documented architecture.

.. requirement:definition:: UseCases.Gate_Traceability_At_Test_Time

:Description: As a safety engineer I want a test that fails when the traceability
chain of a dependable element is incomplete so that an element with
unsatisfied traceability links cannot be released.

.. requirement:definition:: UseCases.Trace_Failure_Modes_To_Interfaces

:Description: As a safety engineer I want failure modes to be traceable to the
public interface elements of the architecture so that every failure
mode is allocated to a concrete part of the design.

.. requirement:definition:: UseCases.Aggregate_Safety_Analysis_Report

:Description: As a safety engineer I want failure modes, control measures and
fault-tree root causes to be aggregated into a single traceability
report so that the completeness of the safety analysis can be
assessed in one place.

.. requirement:definition:: UseCases.Enforce_Certified_Scope_And_Integrity

:Description: As a project lead I want the build to fail when a dependable element
pulls in implementation targets outside its certified scope or
depends on an element of lower integrity level so that certification
boundaries are enforced automatically.

.. requirement:definition:: UseCases.Author_Requirements_In_Rst_Or_Trlc

:Description: As a requirements engineer I want to author requirements either as
RST directives or as TRLC records so that existing RST requirement
sources can be integrated into the traceability chain without manual
rewriting.

.. requirement:definition:: UseCases.Verify_Unit_Tests_Pass

:Description: As a software developer I want unit test results to be captured and
fed into the traceability report so that requirements are only
considered verified when their tests actually pass.

.. requirement:definition:: UseCases.Merge_Cross_Module_Documentation

:Description: As a documentation author I want the HTML documentation of dependent
modules to be merged into a single navigable site with working
cross-references so that a dependable element and its sub-elements
are read as one document.

.. requirement:definition:: UseCases.Forward_AoU_To_Dependees

:Description: As a system integrator I want assumptions of use defined by a
dependable element to be automatically forwarded to the elements
that depend on it so that the integrating project is made aware
of all conditions it must satisfy — including those originating
from transitive dependencies.

.. requirement:definition:: UseCases.Validate_Architecture_Specification_Documents

:Description: As a software architect I want the build to verify that architectural
specification documents (component and sequence diagrams) are consistent
with the implemented Bazel structure so that specification drift is
detected automatically during the build.

.. requirement:definition:: UseCases.Validate_Unit_Specification_Documents

:Description: As a software developer I want the build to verify that unit design
class and sequence diagrams are consistent with the corresponding
implementation artefacts so that unit-level design drift is
detected automatically during the build.