extfs: introduce a tester.

This tester tests that helpers implement the "list" command correctly.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

tests/src/extfs-helpers-listcmd/Makefile.am

@@ -10,11 +10,39 @@ LIBS = $(top_builddir)/lib/libmc.la
 
 # Programs/scripts to build on 'make check'.
 check_PROGRAMS = mc_parse_ls_l
+check_SCRIPTS = run
 
 # Tests to run on 'make check'
 TESTS = run
 
+# On 'make clean', delete 'run' as well.
+CLEANFILES = run
+
 mc_parse_ls_l_SOURCES = \
 	mc_parse_ls_l.c
 
-EXTRA_DIST = run
+data_files_to_distribute = \
+	data/dummy
+
+EXTRA_DIST = mc_xcat test_all $(data_files_to_distribute)
+
+run:
+	echo '#!/bin/sh' > $@
+	echo >> $@
+	echo '# This script is an easy way to launch the "test_all" script' >> $@
+	echo '# with all the required arguments.' >> $@
+	echo '#' >> $@
+	echo '# Run this script with "--help" to learn more.' >> $@
+	echo >> $@
+	echo '# Where to find mc_parse_ls_l and mc_xcat, respectively.' >> $@
+	echo 'PATH="$(abs_builddir):$(abs_srcdir):$$PATH"' >> $@
+	echo >> $@
+# The 'abs_' isn't mandatory. It lets you move this script out of the build tree.
+	echo '"$(abs_srcdir)"/test_all "$$@" \' >> $@
+	echo '  --data-dir "$(abs_srcdir)/data" \' >> $@
+# Before installation, some helpers are in the build tree, some in the src tree.
+	echo '  --helpers-dir "$(abs_top_builddir)/src/vfs/extfs/helpers" \' >> $@
+	echo '  --helpers-dir "$(abs_top_srcdir)/src/vfs/extfs/helpers"' >> $@
+	chmod +x $@
+# (We can alternatively create run from a run.in template
+# with 'AC_CONFIG_FILES[run, chmod +x run]'.)

tests/src/extfs-helpers-listcmd/data/dummy

@@ -0,0 +1,3 @@
+This is a dummy file meant to ensure this directory isn't empty so that git always creates it.
+
+Otherwise our 'test_all' script will fail complaining the directory doesn't exist.

tests/src/extfs-helpers-listcmd/mc_xcat

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+#
+# This program is intended to be identical to 'cat' with the exception that
+# it ignores any arguments past the 1st one.
+#
+# To understand why it's needed, first read the section about
+# MC_TEST_EXTFS_LIST_CMD in the README. As explained there, the command in
+# MC_TEST_EXTFS_LIST_CMD has to ignore any extra arguments passed to it.
+# The tester achieves this by invoking a helper thus (roughly):
+#
+#    export MC_TEST_EXTFS_LIST_CMD="mc_xcat /path/to/fake/input"
+#    sh /path/to/helper list /dev/null
+#
+
+exec cat "$1"

tests/src/extfs-helpers-listcmd/run

@@ -1,15 +0,0 @@
-#!/bin/sh
-
-echo
-echo "This is a placeholder."
-echo "It will be replaced in the future with a script that does the real"
-echo "work of testing the helpers."
-echo
-echo "Here's a silly test to check whether 'ls', had it been an extfs helper,"
-echo "works properly:"
-echo
-
-LC_ALL=C ls -l | ./mc_parse_ls_l
-
-# (LC_ALL=C is meant to prevent date formats MC can't parse. This might
-# still not be foolproof, but that's just a demonstration.)

tests/src/extfs-helpers-listcmd/test_all

@@ -0,0 +1,393 @@
+#!/bin/sh
+
+# A tester for extfs helpers.
+#
+# Copyright (C) 2016
+# The Free Software Foundation, Inc.
+#
+# This file is part of the Midnight Commander.
+#
+# The Midnight Commander is free software: you can redistribute it
+# and/or modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation, either version 3 of the License,
+# or (at your option) any later version.
+#
+# The Midnight Commander is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+help() {
+  cat << EOS
+
+NAME
+
+$(basename "$0") - Tests the 'list' command of extfs helpers.
+
+SYNOPSIS
+
+  $(basename "$0") \\
+     --data-dir /path/to/where/data/files/are/stored \\
+     --helpers-dir /path/to/where/helpers/are/stored
+
+(But you're more likely to invoke this program with the 'run' script
+created by 'make check'; or by 'make check' itself.)
+
+DESCRIPTION
+
+This program tests extfs helpers by feeding them input and comparing
+their output to the expected output.
+
+See README for full details.
+
+You need to tell this program two things: where the helpers are stored,
+and where the "data files" are stored. The data files are *.input files
+that are fed to the helpers and *.output files that are the correct
+output expected from these helpers.
+
+EOS
+}
+
+#"'
+
+############################ Global variables ##############################
+
+# The directories used.
+DATA_DIR=
+HELPERS_DIR1=
+HELPERS_DIR2=
+
+opt_create_output=no        # "yes" if '--create-output' provided.
+opt_run_mcdiff_on_error=no  # "yes" if '--mcdiff' provided.
+
+############################ Coding guidance ###############################
+
+#
+# Portability notes:
+#
+# - We do `local var="$whatever"` instead of `local var=$whatever` for
+#   compatibility with Dash. See http://unix.stackexchange.com/questions/97560.
+#
+# - The 'local' keyword used in this file isn't mandatory. Feel free to
+#   remove it if it isn't supported by your archaic shell.
+#
+
+############################ Utility functions #############################
+
+#
+# Does $1 contain $2?
+#
+# Accepts basic regex.
+#
+has_string() {
+  local haystack="$1"  # quotes needed for Dash, as may contain spaces (see notes above).
+  local needle="$2"
+  echo "$haystack" | grep "$needle" > /dev/null
+}
+
+#
+# Given "/path/to/basename.and.some.ext", returns "basename"
+#
+basename_sans_extensions() {
+  local base="$(basename "$1")"
+  echo "${base%%.*}"
+}
+
+#
+# Does an executable exist?
+#
+has_prog() {
+  # see http://stackoverflow.com/questions/592620
+  command -v "$1" >/dev/null 2>&1
+}
+
+#
+# Can we use colors?
+#
+has_colors() {
+  [ -t 1 ] && has_string "$TERM" 'linux\|xterm\|screen\|tmux\|putty'
+}
+
+init_colors() {
+  if has_colors; then
+    ESC=$(printf '\033')  # for portability
+    C_bold="$ESC[1m"
+    C_green="$ESC[1;32m"
+    C_red="$ESC[1;31m"
+    C_magenta="$ESC[1;35m"
+    C_norm="$ESC[0m"
+  fi
+}
+
+#
+# A few colorful alternatives to 'echo'.
+#
+header()  { echo $C_bold"$@"$C_norm; }
+err()     { echo $C_red"$@"$C_norm; }
+notice()  { echo $C_magenta"$@"$C_norm; }
+success() { echo $C_green"$@"$C_norm; }
+
+die() {
+  err "Error: $@"
+  exit 1
+}
+
+assert_dir_exists() {
+  [ -d "$1" ] || die "The directory '$1' doesn't exist, or is not a directory."
+}
+
+#
+# Creates a temporary file.
+#
+temp_file() {
+  local template="$1"
+  # BSD's doesn't support -t.
+  mktemp "${TMPDIR:-/tmp}/$template"
+}
+
+################################ Main code #################################
+
+#
+# Prints out the command to run a helper, if it can find it.
+#
+# For example,
+#
+#    find_helper uzip /path/to/helpers/dir
+#
+# prints:
+#
+#    /usr/bin/perl -w /path/to/helpers/dir/uzip
+#
+# Since helpers in the build tree don't yet have executable bit set, we
+# need to extract the shebang line.
+#
+find_helper() {
+  local helper_name="$1"
+  local dir="$2"
+
+  local try="$dir/$helper_name"
+  if [ -f "$try" ]; then
+    helper_CMD="$(head -1 $try | cut -c 3-) $try"  # reason #1 we don't allow spaces in pathnames.
+    true
+  else
+    false
+  fi
+}
+
+#
+# The crux of this program.
+#
+run() {
+
+  local error_count=0
+  local pass_count=0
+
+  for INPUT in "$DATA_DIR"/*.input; do
+
+    has_string "$INPUT" '\*' && break  # we can't use 'shopt -s nullglob' as it's bash-specific.
+
+    header "Testing $INPUT"
+
+    has_string "$INPUT" " " && die "Error: filename contains spaces."
+
+    #
+    # Set up variables:
+    #
+
+    local helper_name="$(basename_sans_extensions "$INPUT")"
+    local expected_parsed_output="${INPUT%.input}.output"
+    local env_vars_file="${INPUT%.input}.env_vars"
+    local args_file="${INPUT%.input}.args"
+
+    local do_create_output=no
+
+    if [ ! -f "$expected_parsed_output" ]; then
+      # Corresponding *.output file doesn't exist. We either create it, later, or exit with error.
+      if [ $opt_create_output = "yes" ]; then
+        do_create_output=yes
+      else
+        err
+        err "Missing file: '$expected_parsed_output'."
+        err "You have to create an '.output' file for each '.input' one."
+        err
+        notice "Tip: invoke this program with '--create-output' to"
+        notice "automatically create missing '.output' files."
+        notice
+        exit 1
+      fi
+    fi
+
+    find_helper "$helper_name" "$HELPERS_DIR1" ||
+      find_helper "$helper_name" "$HELPERS_DIR2" ||
+        die "I can't find helper '$helper_name' in either $HELPERS_DIR1 or $HELPERS_DIR2"
+
+    local extra_parser_args=""
+    [ -f "$args_file" ] && extra_parser_args="$(cat "$args_file")"
+
+    local actual_output="$(temp_file $helper_name.actual-output.XXXXXXXX)"
+    local actual_parsed_output="$(temp_file $helper_name.actual-parsed-output.XXXXXXXX)"
+
+    #
+    # Variables are all set. Now do the actual stuff:
+    #
+
+    (
+    MC_TEST_EXTFS_LIST_CMD="mc_xcat $INPUT"  # reason #2 we don't allow spaces in pathnames.
+    export MC_TEST_EXTFS_LIST_CMD
+    if [ -f "$env_vars_file" ]; then
+      set -a  # "allexport: Export all variables assigned to."
+      . "$env_vars_file"
+      set +a
+    fi
+    $helper_CMD list /dev/null > "$actual_output"
+    )
+
+    error_count=$((error_count + 1))  # we'll decrement it later.
+
+    if [ ! -s "$actual_output" ]; then
+       err
+       err "The helper '$helper_name' produced no output for this input. Something is wrong."
+       err
+       err "Make sure this helper supports testability: that it uses \$MC_TEST_EXTFS_LIST_CMD."
+       err
+       err "You may try running the helper yourself with:"
+       err
+       err "  \$ MC_TEST_EXTFS_LIST_CMD=\"mc_xcat $INPUT\" \\"
+       err "      $helper_CMD list /dev/null"
+       err
+       continue
+    fi
+
+    # '--symbolic-ids': uid/gid aren't portable between computers,
+    # of course, so we always represent them symbolically when possible.
+    if ! mc_parse_ls_l --symbolic-ids $extra_parser_args "$actual_output" > "$actual_parsed_output"; then
+       err
+       err "ERROR: Parsing of the output of the helper '$helper_name' has failed."
+       err "This means that $helper_name has produced output that MC won't be able to parse."
+       err "Run the parsing command yourself ('mc_parse_ls_l $extra_parser_args $actual_output')"
+       err "to figure out the problem."
+       err
+       continue
+    fi
+
+    if [ $do_create_output = "yes" ]; then
+      # We arrive here if we were invoked with '--create-output' and
+      # the .output file doesn't exist. We create it and move to the next iteration.
+      cp "$actual_parsed_output" "$expected_parsed_output"
+      notice "The output file has been created in $expected_parsed_output"
+      continue
+    fi
+
+    if ! cmp "$expected_parsed_output" "$actual_parsed_output"; then
+       err
+       err "ERROR: $helper_name has produced output that's different than the expected output."
+       err
+       err "  Expected output (after parsing): $expected_parsed_output"
+       err "  Actual output (after parsing): $actual_parsed_output"
+       err
+       err "This might mean that a bug was introduced into $helper_name. Or that a bug was fixed."
+       err "Please compare the files."
+       err
+       err "If the actual output is the correct one, just copy the latter file"
+       err "onto the former (and commit to the git repository)."
+       err
+       if [ $opt_run_mcdiff_on_error = "yes" ]; then
+         notice "Hit ENTER to launch mcdiff ..."
+         read DUMMY_VAR  # dash needs this.
+         ${MCDIFF:-mcdiff} "$expected_parsed_output" "$actual_parsed_output"
+       else
+         notice "Tip: invoke this program with '--mcdiff' to automatically launch"
+         notice "mcdiff to visually inspect the diff."
+         notice
+       fi
+       continue
+    fi
+
+    rm "$actual_output" "$actual_parsed_output"
+
+    error_count=$((error_count - 1))  # cancel the earlier "+1".
+    pass_count=$((pass_count + 1))
+
+    success "PASSED."
+
+  done
+
+  [ $pass_count = "0" -a $error_count = "0" ] && notice "Note: The data directory contains no *.input files."
+
+  [ $error_count = "0" ]  # exit status of function.
+}
+
+parse_command_line_arguments() {
+  # We want --long-options, so we don't use 'getopts'.
+  while [ -n "$1" ]; do
+    case "$1" in
+      --data-dir)
+        DATA_DIR=$2
+        shift 2
+        ;;
+      --helpers-dir)
+        if [ -z "$HELPERS_DIR1" ]; then
+          HELPERS_DIR1=$2
+        else
+          HELPERS_DIR2=$2
+        fi
+        shift 2
+        ;;
+      --create-output)
+        opt_create_output=yes
+        shift
+        ;;
+      --mcdiff)
+        opt_run_mcdiff_on_error=yes
+        shift
+        ;;
+      --help|-h)
+        help
+        exit
+        ;;
+      *)
+        die "Unknown command-line option $1"
+        ;;
+    esac
+  done
+}
+
+#
+# Check that everything is set up correctly.
+#
+verify_setup() {
+  [ -n "$DATA_DIR" ] || die "You didn't specify the data dir (--data-dir). Run me with --help for info."
+  [ -n "$HELPERS_DIR1" ] || die "You didn't specify the helpers dir (--helpers-dir). Run me with --help for info."
+  [ -z "$HELPERS_DIR2" ] && HELPERS_DIR2=$HELPERS_DIR1  # we're being lazy.
+
+  local dir
+  for dir in "$DATA_DIR" "$HELPERS_DIR1" "$HELPERS_DIR2"; do
+    assert_dir_exists "$dir"
+    has_string "$dir" " " && die "$dir: Sorry, spaces aren't allowed in pathnames."  # search "reason", twice, above.
+  done
+
+  local missing_progs=""
+  check_prog() {
+    if ! has_prog "$1"; then
+      err "I can't see the program '$1'."
+      missing_progs="${missing_progs}${missing_progs:+ and }'$1'"
+    fi
+  }
+
+  check_prog "mc_parse_ls_l"
+  check_prog "mc_xcat"
+  check_prog "mktemp"  # non-POSIX
+  [ -z "$missing_progs" ] || die "You need to add to your PATH the directories containing the executables $missing_progs."
+}
+
+main() {
+  init_colors
+  parse_command_line_arguments "$@"
+  verify_setup
+  run  # being the last command executed, its exit status is that of this whole script.
+}
+
+main "$@"