ci: use gcovr 5.0 to generate code coverage reports

Change-Id: I680b476bb93cffff389071437e7a818f16b6334d

.jenkins

@@ -2,6 +2,9 @@
 set -e
 source .jenkins.d/util.sh
 
+if has Linux $NODE_LABELS; then
+    export PATH="~/.local/bin${PATH:+:}${PATH}"
+fi
 export CACHE_DIR=${CACHE_DIR:-/tmp}
 export WAF_JOBS=${WAF_JOBS:-1}
 [[ $JOB_NAME == *"code-coverage" ]] && export DISABLE_ASAN=yes

.jenkins.d/00-deps.sh

@@ -35,7 +35,8 @@ elif has Ubuntu $NODE_LABELS; then
 
     case $JOB_NAME in
         *code-coverage)
-            sudo apt-get -qy install gcovr lcov
+            sudo apt-get -qy install lcov python3-pip
+            pip3 install --user --upgrade --upgrade-strategy=eager 'gcovr~=5.0'
             ;;
         *Docs)
             sudo apt-get -qy install python3-pip

.jenkins.d/30-coverage.sh

@@ -2,29 +2,30 @@
 set -ex
 
 if [[ $JOB_NAME == *"code-coverage" ]]; then
-    gcovr --object-directory=build \
-          --output=build/coverage.xml \
-          --exclude="$PWD/tests" \
-          --root=. \
-          --xml
+    # Generate an XML report (Cobertura format) and a detailed HTML report using gcovr
+    # Note: trailing slashes are important in the paths below. Do not remove them!
+    gcovr -j$WAF_JOBS \
+          --object-directory build \
+          --filter tools/ \
+          --exclude-throw-branches \
+          --exclude-unreachable-branches \
+          --print-summary \
+          --html-details build/gcovr/ \
+          --xml build/coverage.xml
 
-    # Generate also a detailed HTML output, but using lcov (better results)
+    # Generate a detailed HTML report using lcov
     lcov --quiet \
          --capture \
          --directory . \
+         --exclude "$PWD/tests/*" \
          --no-external \
          --rc lcov_branch_coverage=1 \
-         --output-file build/coverage-with-tests.info
-
-    lcov --quiet \
-         --remove build/coverage-with-tests.info "$PWD/tests/*" \
-         --rc lcov_branch_coverage=1 \
          --output-file build/coverage.info
 
     genhtml --branch-coverage \
             --demangle-cpp \
             --legend \
-            --output-directory build/coverage \
+            --output-directory build/lcov \
             --title "ndn-tools unit tests" \
             build/coverage.info
 fi