Added code coverage feature

[jackctj117]

Added gcovr code coverage for tests

[Copilot]

Pull Request Overview

This PR adds code coverage functionality to the test suite using gcovr. The implementation provides both automated and manual workflows for generating coverage reports in various formats (HTML, XML, JSON) with customizable filtering and threshold options.

• Added gcovr-based code coverage support with compiler instrumentation flags
• Implemented convenient make coverage target for automated coverage workflow
• Added comprehensive documentation with installation, usage, and customization examples

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 2 comments.

File	Description
test/Makefile	Added coverage build flags, clean targets for coverage files, and automated coverage target
test/README.md	Added detailed documentation covering installation, usage, and configuration options for code coverage

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Pull Request Overview

Copilot reviewed 2 out of 3 changed files in this pull request and generated no new comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 2 out of 3 changed files in this pull request and generated no new comments.

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[bigbrett]

@jackctj117 when I run make coverage this is the coverage report I see generated

This doesn't seem right? From the build output:

Generating coverage report...
cd .. && mkdir -p coverage && gcovr --root . \
        --filter 'src/.*' \
        --filter 'wolfhsm/.*' \
        --html-details coverage/index.html \
        --print-summary
lines: 0.0% (0 out of 0)
branches: 0.0% (0 out of 0)