feat: add script to generate coverage

.gitignore

@@ -1 +1,2 @@
+/coverage
 /target

scripts/cov.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+# Build HTML coverage report. Requires Rust 1.60+ with llvm-tools-preview component
+# Run this script from the root directory of the repo.
+
+set -eux
+
+ROOT_PATH=$(dirname "$(readlink -f "$0")")/..
+
+cd $ROOT_PATH
+rm -rf ./coverage
+
+export LLVM_PROFILE_FILE="$ROOT_PATH/coverage/profiles/%p.profraw"
+
+# Run all tests with coverage
+RUSTFLAGS="-C instrument-coverage" cargo test --all-features
+
+# Merge different profraw files
+$(rustc --print sysroot)/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-profdata \
+    merge -sparse ./coverage/profiles/*.profraw -o coverage/profiles/merge.profdata
+
+# Build list of executables, should be the list of test binaries :/
+BINS=$(find target/debug/deps -type f -executable | grep -v '.so$')
+
+# Generate HTML report in coverage directory
+$(rustc --print sysroot)/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-cov \
+    show --Xdemangler=rustfilt \
+    $(echo $BINS | xargs -d' ' -I{} echo --object '{}') \
+    --instr-profile=./coverage/profiles/merge.profdata \
+    --show-line-counts-or-regions \
+    --show-instantiations \
+    --ignore-filename-regex='/.cargo/(registry|git)' \
+    --use-color \
+    --output-dir coverage \
+    --format html