use grcov to get rust code coverage

scripts/coverage.sh

@@ -0,0 +1,88 @@
+#!/bin/bash
+readonly GRCOV_DOWNLOAD="https://github.com/mozilla/grcov/releases/download/v0.8.2/grcov-linux-x86_64.tar.bz2"
+readonly TMP_DIR=$(pwd)/tmp
+readonly PROJECT_ROOT=$(pwd)
+readonly GRCOV_TARBAL="$TMP_DIR/grcov.tar.bz2"
+readonly GRCOV="$TMP_DIR/grcov"
+
+clean_up() {
+	cd $PROJECT_ROOT
+	/bin/rm default.profraw  lcov.info *.profraw || true
+	cd target
+	/bin/rm default.profraw  lcov.info *.profraw || true
+	cargo clean
+}
+
+check_arg(){
+    if [ -z $1 ]
+    then
+        help
+        exit 1
+    fi
+}
+
+match_arg() {
+    if [ $1 == $2 ] || [ $1 == $3 ]
+    then
+        return 0
+    else
+        return 1
+    fi
+}
+
+
+download() {
+	if [ ! -e $GRCOV ]; 
+	then 
+		echo "[*] Downloading grcov"
+		wget --quiet  --output-doc=$GRCOV_TARBAL $GRCOV_DOWNLOAD;
+		cd $TMP_DIR
+		tar -xf $GRCOV_TARBAL;
+		cd $PROJECT_ROOT
+	fi
+}
+
+build_and_test() {
+	export RUSTFLAGS="-Zinstrument-coverage"
+	cd $PROJECT_ROOT
+
+	echo "[*] Building project"
+	cargo build
+
+	export LLVM_PROFILE_FILE="target/libmedium-%p-%m.profraw"
+
+	echo "[*] Running tests"
+    cargo test
+
+	echo "[*] Generating coverage"
+	$GRCOV target/ --binary-path  \
+		./target/debug/ \
+		-s . -t lcov --branch \
+		--ignore-not-existing \
+		--ignore "../*" -o target/lcov.info
+
+	$GRCOV target/ --binary-path  \
+		./target/debug/ \
+		-s . -t html --branch \
+		--ignore-not-existing \
+		--ignore "../*" -o target/coverage.html
+
+}
+
+run_coverage() {
+	cd $PROJECT_ROOT
+	mkdir $TMP_DIR || true
+	clean_up
+	download
+	build_and_test
+}
+
+check_arg $1
+
+if match_arg $1 'c' '--coverage'
+then
+	run_coverage
+else
+	echo "undefined option"
+	exit 1
+fi