Tests: tweak test build script

Do a rebuild from scratch only if requested. This allows fast local testing of new or changes test cases.
Don't need to call gcov ourselves as this is done by codecov too.

tests/executeUnitTests.sh

@@ -20,9 +20,11 @@
 # Script to execute googletest based unit tests for BOINC
 
 # Usage:
-#  ./tests/executeUnitTests.sh [--report-coverage]
+#  ./tests/executeUnitTests.sh [--report-coverage] [--clean]
 #
 # if --report-coverage is given the test coverage will be reported to codecov.io
+# if --clean is given the tests will be rebuild from scratch otherwise an existing
+# build directory is used
 
 # check working directory because the script needs to be called like: ./tests/executeUnitTests.sh
 if [ ! -d "tests" ]; then
@@ -33,12 +35,16 @@ fi
 ROOTDIR=$(pwd)
 CI_RUN="${TRAVIS:-false}"
 report=""
+doclean=""
 while [[ $# -gt 0 ]]; do
     key="$1"
     case $key in
         --report-coverage)
         report="yes"
         ;;
+        --clean)
+        doclean="yes"
+        ;;
         *)
         echo "unrecognized option $key"
         ;;
@@ -54,11 +60,11 @@ if [ "${report}" = "yes" ]; then
 fi
 
 cd tests || exit 1
-if [ -d "gtest" ]; then
+if [[ "$doclean" = "yes" && -d "gtest" ]]; then
     rm -rf gtest
     if [ $? -ne 0 ]; then cd ..; exit 1; fi
 fi
-mkdir gtest
+mkdir -p gtest
 if [ $? -ne 0 ]; then cd ..; exit 1; fi
 cd gtest
 cmake ../unit-tests
@@ -72,8 +78,8 @@ done
 
 cd ../..
 if [ "${report}" = "yes" ]; then
-    for T in lib sched; do
-        [ -d "${T}" ] && gcov -lp *.o >/dev/null;
-    done
+    #for T in lib sched; do
+    #    [ -d "${T}" ] && gcov -lp *.o >/dev/null;
+    #done
     codecov
 fi