Add basic code coverage

.github/workflows/coverage.yml

@@ -0,0 +1,28 @@
+name: coverage
+
+on: [push]
+jobs:
+  test:
+    name: coverage
+    runs-on: ubuntu-latest
+    container:
+      image: xd009642/tarpaulin:0.30.0
+      options: --security-opt seccomp=unconfined
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Generate code coverage
+        run: |
+          cargo tarpaulin --tests --examples --verbose --all-features --workspace --timeout 120 --out xml
+
+      - name: Workaround for codecov/feedback#263
+        run: |
+          git config --global --add safe.directory "$GITHUB_WORKSPACE" 
+
+      - name: Upload to codecov.io
+        uses: codecov/[email protected]
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: true
+

README.md

@@ -1,4 +1,4 @@
-# halo2 [![Crates.io](https://img.shields.io/crates/v/halo2.svg)](https://crates.io/crates/halo2) #
+# halo2 [![Crates.io](https://img.shields.io/crates/v/halo2.svg)](https://crates.io/crates/halo2) [![codecov](https://codecov.io/github/privacy-scaling-explorations/halo2/graph/badge.svg?token=6WX7KBHFIP)](https://codecov.io/github/privacy-scaling-explorations/halo2)
 
 ## [Documentation](https://privacy-scaling-explorations.github.io/halo2/halo2_proofs)
 

halo2_proofs/tests/frontend_backend_split.rs

@@ -505,7 +505,7 @@ const WIDTH_FACTOR: usize = 1;
 
 #[test]
 fn test_mycircuit_full_legacy() {
-    #[cfg(feature = "heap-profiling")]
+    #[cfg(all(feature = "heap-profiling", not(tarpaulin)))]
     let _profiler = dhat::Profiler::new_heap();
 
     use halo2_proofs::plonk::{
@@ -566,7 +566,7 @@ fn test_mycircuit_full_legacy() {
 fn test_mycircuit_full_split() {
     use halo2_middleware::zal::impls::{H2cEngine, PlonkEngineConfig};
 
-    #[cfg(feature = "heap-profiling")]
+    #[cfg(all(feature = "heap-profiling", not(tarpaulin)))]
     let _profiler = dhat::Profiler::new_heap();
 
     let engine = PlonkEngineConfig::new()