Add shellcheck and pre-commit to CI jobs

.github/workflows/nestbuildmatrix.yml

@@ -78,7 +78,8 @@ jobs:
     # formatting in their editor consistently.
     # https://github.com/pre-commit/pre-commit-hooks?tab=readme-ov-file#mixed-line-ending
     #
-    # This check makes sure the repository is always consistent NL line endings.
+    # This check makes sure the files in the repository are always consistent
+    # in their line endings, i.e. new line, and not carrige return+line feed.
     runs-on: "ubuntu-20.04"
     steps:
       - name: "Checkout repository content"

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.4.0
+    rev: v5.0.0
     hooks:
       - id: end-of-file-fixer
       - id: trailing-whitespace

testsuite/do_tests.sh

@@ -178,7 +178,14 @@ list_files() {
     # instead use list_files like
     #
     #   list_files <somedir> <some_pattern> | while read -r test_name; do ... done
-    find "${1}" -maxdepth 1 -name "${2}" -printf '%f\n'
+    if test "${INFO_OS}" = "Darwin"; then
+        # ref https://stackoverflow.com/a/752893
+        # Note that on GNU systems an additional '-r' would be needed for
+        # xargs, which is not available here.
+        find "${1}" -maxdepth 1 -name "${2}" -print0 | xargs -0 -n1 basename
+    else
+        find "${1}" -maxdepth 1 -name "${2}" -printf '%f\n'
+    fi
 }
 
 echo "================================================================================"

testsuite/junit_xml.sh

@@ -114,7 +114,7 @@ junit_write ()
         bail_out 'junit_write: report file not open, call junit_open first!'
     fi
 
-    if test -z "$1" -o -z "$2"; then
+    if test -z "$1" -o -z "$2"; then  # Note: this aborts due to "undefined variable", not because of `-z`
         bail_out 'junit_write: classname and testname arguments are mandatory!'
     fi
 
@@ -126,8 +126,9 @@ junit_write ()
         fi
 
         if test "$3" = "failure" ; then
-            echo "    <failure message=\"$4\" type=\"\"><![CDATA["
-            echo "${5/]]>/]]>]]\&gt;<\![CDATA[}"
+            msgdata="${5:-}"
+            echo "    <failure message=\"${4:-}\" type=\"\"><![CDATA["
+            echo "${msgdata/]]>/]]>]]\&gt;<\![CDATA[}"
             echo "]]></failure>"
         fi
         echo "  </testcase>"