chore: add coverage badge and script

README.md

@@ -2,10 +2,10 @@
 > Markdown Table of Content generator
 
 ![](https://github.com/kevingimbel/mktoc/workflows/Clippy%20check/badge.svg)
+![Coverage](assets/coverage/flat.svg)
 
 # Table of Contents
 <!-- BEGIN mktoc {"min_depth":2} -->
-
 - [About](#about)
 - [Installation](#installation)
   - [Cargo](#cargo)

helpers/coverage.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+export LLVM_PROFILE_FILE="fd-%p-%m.profraw"
+export RUSTFLAGS="-Cinstrument-coverage"
+
+# build project
+cargo build
+
+# run tests to create the profraw files needed by grcov
+cargo test
+
+# run grcov with "defaults", this is straight up taken from their README 
+grcov . -s . --binary-path ./target/debug/ -t html --branch --ignore-not-existing -o ./target/debug/coverage/
+
+# copy badge to asset directory
+cp target/debug/coverage/badges/flat.svg assets/coverage
+
+# cleanup
+rm ./*.profraw