ci: upload code coverage to Codecov

.github/workflows/ci.yml

@@ -45,7 +45,8 @@ jobs:
       - uses: Swatinem/[email protected]
       - name: Rust setup
         # FIXME: Once rustup adds a command to install a toolchain from rust-toolchain.toml, we can remove this.
-        run: rustup toolchain add 1.73.0 --profile minimal
+        run: rustup toolchain add 1.73.0 --profile minimal --component llvm-tools-preview
+      - uses: taiki-e/install-action@cargo-llvm-cov
 
       - name: Lint
         run: make lint
@@ -58,8 +59,16 @@ jobs:
         # (to avoid building both a release and a debug profile in CI).
         run: PROFILE=dev make build
 
-      - name: Run unit tests
-        run: make test-unit
+      - name: Run unit tests (and generate coverage)
+        run: make ci-cov
+
+      - name: Upload coverage to Codecov
+        uses: codecov/[email protected]
+        with:
+          files: codecov.json
+          fail_ci_if_error: true
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
   build-docs:
     name: Build Documentation

Makefile

@@ -122,4 +122,10 @@ fmt-check: fmt-nix-check fmt-rust-check fmt-js-check
 lint:
 	@touch $(CLI_KERNEL_PATH)
 	@cargo clippy -- --no-deps -D warnings -A clippy::let_underscore_future -A clippy::module_inception -A clippy::op_ref -A clippy::manual_strip -A clippy::missing_safety_doc -A clippy::slow_vector_initialization -A clippy::empty_loop -A clippy::collapsible-match
-	@rm -f $(CLI_KERNEL_PATH)
+	@rm -f $(CLI_KERNEL_PATH)
+
+.PHONY: ci-cov 
+ci-cov:
+# This will only generate a coverage report for unit tests. We should add coverage
+# for integration tests as well.
+	@cargo llvm-cov --lib --bins --codecov --output-path codecov.json

README.md

@@ -1,5 +1,7 @@
 # 👨‍⚖️ jstz
 
+[![codecov](https://codecov.io/gh/jstz-dev/jstz/graph/badge.svg?token=FA7IPI5Q9J)](https://codecov.io/gh/jstz-dev/jstz)
+
 `jstz` (pronounced: "justice") is a JavaScript runtime powered by Tezos Smart Optimistic Rollups that uses [Boa](https://boajs.dev/) and is built in [Rust](https://www.rust-lang.org/).
 
 ## Install

codecov.yml

@@ -0,0 +1,22 @@
+# Configures a simple CI comment (instead of the more verbose default)
+comment:
+  layout: "header, files, footer"
+  hide_project_coverage: false
+
+# Configures coverage checks -- both patch and project-wide checks
+# can drop by 5% before failing the CI build.
+#
+# Note: duplication required since the `default_rules` do not support
+# the `target`, `threshold`, or `if_ci_failed` fields.
+coverage:
+  status:
+    project:
+      default:
+        target: auto
+        threshold: 5%
+        if_ci_failed: success
+    patch:
+      default:
+        target: auto
+        threshold: 5%
+        if_ci_failed: success