pre-commit: run optional doctests before commit

 * Any error will not prevent the commit but will warn the
   developer. This is being done due to livestatus package
   import problems in some packages.

Change-Id: I9cbad5d9762bfdf4e16918a66921842ec7cfa04c

.pre-commit-config.yaml

@@ -54,6 +54,12 @@ repos:
             entry: scripts/check-pylint
             language: script
             types: [file, python]
+          - id: doctest
+            name: Doctests
+            entry: scripts/run-doctests
+            language: script
+            types: [file, python]
+            verbose: true
           - id: futurize
             name: Check futurize
             entry: scripts/check-futurize

scripts/run-doctests

@@ -0,0 +1,39 @@
+#!/bin/bash
+#
+# This file is for execution by the pre-commit framework.
+#
+source "$(dirname $0)/lib-precommit"
+
+# Filter out all tests/* and tests-py3/* files.
+declare -a FILES
+
+for param in "$@"; do
+    if [[ "$param" == tests* ]]; then
+        continue
+    fi
+    FILES+=($param)
+done
+
+NUM_PARAM=${#FILES[@]}
+
+if [ "$NUM_PARAM" == "0" ]; then
+    echo No files to check. >&2
+    exit 0
+fi
+
+REPO_PATH="$(git rev-parse --show-toplevel)"
+PIPENV="$REPO_PATH/scripts/run-pipenv"
+
+printf -v files " %s" ${FILES[@]}
+PYTHON2_FILES=$(python_files 2 "$files")
+PYTHON3_FILES=$(python_files 3 "$files")
+
+if [ ! -z "$PYTHON2_FILES" ]; then
+    $PIPENV 2 run python -m doctest $PYTHON2_FILES
+fi
+
+if [ ! -z "$PYTHON3_FILES" ]; then
+    $PIPENV 3 run python -m doctest $PYTHON3_FILES
+fi
+
+exit 0