Add code coverage to the CI

.github/codecov.yml

@@ -0,0 +1,10 @@
+coverage:
+  status:
+    project:
+      default:
+        target: 89%      # the required coverage value
+        threshold: 0.5%  # the leniency in hitting the target
+    patch:
+      default:
+        target: 90%      # the required coverage value
+        threshold: 0.5%  # the leniency in hitting the target

.github/workflows/check.yml

@@ -7,13 +7,15 @@ on:
       - "ipa-*/src/**/*"
       - "ipa-core/benches/**/*"
       - "ipa-core/tests/**/*"
+      - ".github/**/*"
   pull_request:
     paths:
       - "**/Cargo.toml"
       - "**/Cargo.lock"
       - "ipa-*/src/**/*"
       - "ipa-core/benches/**/*"
       - "ipa-core/tests/**/*"
+      - ".github/**/*"
   workflow_dispatch:
 
 env:
@@ -155,3 +157,32 @@ jobs:
         run: rustup component add rust-src
       - name: Run tests with sanitizer
         run: RUSTFLAGS="-Z sanitizer=${{ matrix.sanitizer }} -Z sanitizer-memory-track-origins" cargo test -Z build-std --target $TARGET --no-default-features --features "cli web-app real-world-infra test-fixture descriptive-gate"
+
+  coverage:
+    name: Measure coverage
+    runs-on: ubuntu-latest
+    env:
+      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+
+      - name: Install rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: llvm-tools
+
+      - name: Install cargo-llvm-cov
+        run: cargo install cargo-llvm-cov
+
+      - name: Measure coverage
+        run: ./scripts/coverage-ci --lcov --output-path ipa.cov
+
+      - name: Report to codecov.io
+        uses: codecov/codecov-action@v3
+        with:
+          file: ipa.cov
+          fail_ci_if_error: false
+

scripts/coverage-ci

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# shamelessly stolen from https://github.com/rustls/rustls/blob/c296594db33c7d50ab642ab48f8302e6a88dcebf/admin/coverage
+
+set -e
+
+source <(cargo llvm-cov show-env --export-prefix)
+cargo llvm-cov clean --workspace
+
+cargo build --all-targets
+
+# Need to be kept in sync manually with tests we run inside check.yml.
+cargo test
+for gate in "compact" "descriptive"; do
+  cargo test --no-default-features --features "cli web-app real-world-infra test-fixture $gate-gate"
+done
+
+cargo llvm-cov report "$@"