Make testing within Docker containers easier

docker/run-stow-tests.sh

@@ -22,11 +22,12 @@
 . /usr/local/perlbrew/etc/bashrc
 
 # Standard safety protocol
-set -euf -o pipefail
+set -ef -o pipefail
 IFS=$'\n\t'
 
-for p_version in $(perlbrew list | sed 's/ //g'); do
-    perlbrew use $p_version
+test_perl_version () {
+    perl_version="$1"
+    perlbrew use $perl_version
 
     echo $(perl --version)
 
@@ -40,6 +41,33 @@ for p_version in $(perlbrew list | sed 's/ //g'); do
     make distcheck
     perl Build.PL && ./Build build && cover -test
     ./Build distcheck
-done
+}
 
-make distclean
+if [[ -n "$LIST_PERL_VERSIONS" ]]; then
+    echo "Listing Perl versions available from perlbrew ..."
+    perlbrew list
+elif [[ -z "$PERL_VERSION" ]]; then
+    echo "Testing all versions ..."
+    for perl_version in $(perlbrew list | sed 's/ //g'); do
+        test_perl_version $perl_version
+    done
+    make distclean
+else
+    echo "Testing with Perl $PERL_VERSION"
+    # Test a specific version requested via $PERL_VERSION environment
+    # variable.  Make sure set -e doesn't cause us to bail on failure
+    # before we start an interactive shell.
+    test_perl_version $PERL_VERSION || :
+    # N.B. Don't distclean since we probably want to debug this Perl
+    # version interactively.
+    cat <<EOF
+To run a specific test, type something like:
+
+perl -Ilib -Ibin -It t/cli_options.t
+
+Code can be edited on the host and will immediately take effect inside
+this container.
+
+EOF
+    bash
+fi