feat(ci): Add codecov (#233)

Adds codecov to CI

.github/codecov.yml

@@ -0,0 +1,25 @@
+# ref: https://docs.codecov.com/docs/codecovyml-reference
+coverage:
+  # TODO: Raise coverage requirements
+  range: 25..100
+  round: down
+  precision: 1
+  status:
+    # ref: https://docs.codecov.com/docs/commit-status
+    project:
+      default:
+        # Avoid false negatives
+        threshold: 1%
+
+ignore:
+  - "tests"
+  - "test_util*"
+  - "test_utils"
+  - "bin/programs/minimal"
+  - "bin/programs/simple-revm"
+
+# Make comments less noisy
+comment:
+  layout: "condensed_header, condensed_files, condensed_footer"
+  require_changes: true
+  hide_project_coverage: false

.github/workflows/rust_ci.yaml

@@ -96,3 +96,36 @@ jobs:
         run: just lint-docs
       - name: doctest
         run: just test-docs
+  coverage:
+    runs-on: ubuntu-latest
+    name: codecov
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install stable
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: llvm-tools-preview
+      - name: Rust cache
+        uses: Swatinem/rust-cache@v2
+        with:
+          cache-on-failure: true
+      - name: cargo install cargo-llvm-cov
+        uses: taiki-e/install-action@cargo-llvm-cov
+      - name: cargo install cargo-nextest
+        uses: taiki-e/install-action@nextest
+      - name: cargo generate-lockfile
+        if: hashFiles('Cargo.lock') == ''
+        run: cargo generate-lockfile
+      - name: cargo llvm-cov
+        run: cargo llvm-cov nextest --locked --workspace --lcov --output-path lcov.info
+      - name: Record Rust version
+        run: echo "RUST=$(rustc --version)" >> "$GITHUB_ENV"
+      - name: Upload to codecov.io
+        uses: codecov/codecov-action@v4
+        with:
+          fail_ci_if_error: true
+          token: ${{ secrets.CODECOV_TOKEN }}
+          env_vars: OS,RUST
+          files: lcov.info