add Codecov

Author: NailxSharipov

.github/workflows/tests.yml

@@ -16,3 +16,14 @@ jobs:
       - name: Run tests
         working-directory: iOverlay
         run: cargo test
+      - name: Install tarpaulin
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-tarpaulin
+      - name: Run coverage
+        working-directory: iOverlay
+        run: cargo tarpaulin --out Lcov
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v4
+        with:
+          files: iOverlay/lcov.info

iOverlay/README.md

@@ -3,6 +3,7 @@
 [![crates.io version](https://img.shields.io/crates/v/i_overlay.svg)](https://crates.io/crates/i_overlay)
 [![docs.rs docs](https://docs.rs/i_overlay/badge.svg)](https://docs.rs/i_overlay)
 [![tests](https://github.com/iShape-Rust/iOverlay/actions/workflows/tests.yml/badge.svg)](https://github.com/iShape-Rust/iOverlay/actions/workflows/tests.yml)
+[![codecov](https://codecov.io/gh/iShape-Rust/iOverlay/branch/main/graph/badge.svg)](https://codecov.io/gh/iShape-Rust/iOverlay)
 
 ![Balloons](readme/balloons.svg)