diff --git a/.travis/utils.sh b/.travis/utils.sh
new file mode 100644
index 0000000..3da971b
--- /dev/null
+++ b/.travis/utils.sh
@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: MIT
+#
+# Auxiliary functions and variables.
+#
+# Usage: . utils.sh
+
+# All variables prefixed with __lsr_ are internal.
+
+# Code that prints the version of Python interpreter to standard output; it
+# should be compatible across Python 2 and Python 3, the version is printed as
+# "{major}.{minor}".
+__lsr_get_python_version_py='
+import sys
+
+sys.stdout.write("%s.%s\n" % sys.version_info[:2])
+'
+
+# Colors for lsr_banner, lsr_info, and lsr_error.
+__lsr_color_reset='\e[0m'
+__lsr_color_red='\e[31m'
+__lsr_color_blue='\e[34m'
+__lsr_color_yellow='\e[1;33m'
+
+##
+# lsr_banner $1 [$2]
+#
+#   $1 - banner text
+#   $2 - number of columns to occupy (default: 79)
+#
+# Print banner (in yellow) with $1 to stdout.
+function lsr_banner() {
+  local maxlen=${2:-79}
+  local fillchar='_'
+  local text=" ${1} "
+  local fillsize=$(( ${maxlen} - ${#text} ))
+  local line1
+  local line2
+
+  if [[ ${fillsize} -lt 0 ]]; then
+    maxlen=${#text}
+    fillsize=0
+  fi
+
+  line1=$(printf "%*s" ${maxlen} "" | tr " " "${fillchar}")
+
+  if [[ $(( ${fillsize} % 2 )) -eq 1 ]]; then
+    text="${text} "
+  fi
+
+  line2=$(printf "%*s" $(( ${fillsize} / 2 )) "" | tr " " "${fillchar}")
+  line2="${line2}${text}${line2}"
+
+  echo -e "${__lsr_color_yellow}${line1}${__lsr_color_reset}"
+  echo -e "${__lsr_color_yellow}${line2}${__lsr_color_reset}"
+}
+
+##
+# lsr_info ARGS
+#
+# Print ARGS (in blue) to stdout.
+function lsr_info() {
+  echo -e "${__lsr_color_blue}$*${__lsr_color_reset}"
+}
+
+##
+# lsr_error ARGS
+#
+# Print ARGS (in red) to stderr and exit with exit code 1.
+function lsr_error() {
+  echo -e "${__lsr_color_red}$*${__lsr_color_reset}" >&2
+  exit 1
+}
+
+##
+# lsr_get_python_version $1
+#
+#   $1 - command or full path to Python interpreter
+#
+# If $1 is installed, return its version.
+function lsr_get_python_version() {
+  if command -v $1 >/dev/null 2>&1; then
+    $1 -c "${__lsr_get_python_version_py}"
+  fi
+}
+
+##
+# lsr_compare_versions $1 $2 $3
+#
+#   $1 - version string (see notes below)
+#   $2 - binary operation (see TEST(1))
+#   $3 - version string (see notes below)
+#
+# Exit with 0 if `$1 $2 $3`.
+#
+# Notes:
+#   A version string is of the format [:digit:] "." [:digit:].
+function lsr_compare_versions() {
+  if [[ $# -lt 3 ]]; then
+    return 1
+  fi
+
+  test ${1//./} $2 ${3//./}
+}
+
+##
+# lsr_check_python_version $1 $2 $3
+#
+#   $1 - command or full path to Python interpreter
+#   $2 - binary operation (see TEST(1))
+#   $3 - version string in [:digit:] "." [:digit:] format.
+#
+# Exit with 0 if `version($1) $2 $3`.
+function lsr_check_python_version() {
+  if [[ $# -lt 3 ]]; then
+    return 1
+  fi
+
+  lsr_compare_versions $(lsr_get_python_version $1) $2 $3
+}
+
+##
+# lsr_compare_pythons $1 $2 $3
+#
+#   $1 - command or full path to Python interpreter
+#   $2 - binary operation (see TEST(1))
+#   $3 - command or full path to Python interpreter
+#
+# Exit with 0 if `version($1) $2 version($3)`.
+function lsr_compare_pythons() {
+  if [[ $# -lt 3 ]]; then
+    return 1
+  fi
+
+  lsr_compare_versions \
+    $(lsr_get_python_version $1) $2 $(lsr_get_python_version $3)
+}