https://github.com/shenxianpeng/gcov-example

Use Gcov + LCOV/gcovr to show C/C++ projects code coverage results
https://github.com/shenxianpeng/gcov-example

code-coverage coverage gcov gcovr lcov

Last synced: 3 days ago
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Use Gcov + LCOV/gcovr to show C/C++ projects code coverage results

• Host: GitHub
• URL: https://github.com/shenxianpeng/gcov-example
• Owner: shenxianpeng
• License: mit
• Created: 2021-07-11T11:27:21.000Z (over 3 years ago)
• Default Branch: master
• Last Pushed: 2024-10-11T07:43:05.000Z (2 months ago)
• Last Synced: 2024-12-19T06:08:06.224Z (4 days ago)
• Topics: code-coverage, coverage, gcov, gcovr, lcov
• Language: Makefile
• Homepage: https://shenxianpeng.github.io/gcov-example/
• Size: 179 KB
• Stars: 43
• Watchers: 2
• Forks: 18
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

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README

        
# Gcov Example

**Use [Gcov](https://gcc.gnu.org/onlinedocs/gcc/Gcov.html) + [LCOV](https://github.com/linux-test-project/lcov) / [gcovr](https://github.com/gcovr/gcovr) to show C/C++ projects code coverage results.**

[![pages-build-deployment](https://github.com/shenxianpeng/gcov-example/actions/workflows/pages/pages-build-deployment/badge.svg)](https://github.com/shenxianpeng/gcov-example/actions/workflows/pages/pages-build-deployment) [![Build](https://github.com/shenxianpeng/gcov-example/actions/workflows/build.yml/badge.svg)](https://github.com/shenxianpeng/gcov-example/actions/workflows/build.yml)

This repo shows how to use Gcov to create lcov/gcovr coverage reports for C/C++ projects.

**Code coverage reports online**

* 📄 [LCOV - code coverage report](https://shenxianpeng.github.io/gcov-example/lcov-report/index.html)

* 📄 [gcovr - code coverage report](https://shenxianpeng.github.io/gcov-example/gcovr-report/coverage.html)

Note: The source code is under the `master` branch, and code coverage report under branch `coverage`.

## What problem does Gcov solve

The problem I encountered: A C/C++ project from decades ago has no unit tests, only regression tests. But I want to know:

* What code is tested by regression tests? 

* Which code is untested?

* What is the code coverage? 

* Where do I need to improve automated test cases in the future?

Can code coverage be measured without unit tests? The answer is Yes.

There are some tools on the market that can measure the code coverage of black-box testing, such as Squish Coco, Bullseye, etc but need to be charged. their principle is to insert instrumentation during build.

I tried Squish Coco but I have some build issues are not resolved.

## How Gcov works

Gcov workflow diagram

![flow](img/gcov-flow.jpg)

There are three main steps:

1. Adding special compile options to the GCC compilation to generate the executable, and `*.gcno`.

2. Running (testing) the generated executable, which generates the `*.gcda` data file.

3. With `*.gcno` and `*.gcda`, generate the `gcov` file from the source code, and finally generate the code coverage report.

Here's how each of these steps is done exactly.

## Getting started

You can clone this repository and run `make help` to see how to use it.

```bash

$ git clone https://github.com/shenxianpeng/gcov-example.git

cd gcov-example

$ make help

help                           Makefile help

build                          Make build

coverage                       Run code coverage

lcov-report                    Generate lcov report

gcovr-report                   Generate gcovr report

deps                           Install dependencies

clean                          Clean all generate files

lint                           Lint code with clang-format

```

Steps to generate code coverage reports

```bash

# 1. compile

make build

# 2. run executable

./main

# 3. run code coverage

make coverage

# 4. generate report

# support lcov and gcovr reports

# to make report need to install dependencies first

make deps

# then

make lcov-report

# or

make gcovr-report

```