testsuite: add script for finding the previous release tag

Change-Id: I744f33dc14fc195b82a0b502277d7ce9f10e0fca

testsuite/find-previous-major-release-tag.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+set -ueo pipefail
+
+# This script finds the previous major tag from the current HEAD position.
+
+closestHeadVersion="$(git describe --tags)"
+
+sortedTags="$(git tag --list --sort -version:refname)"
+
+verlte() {
+    # sort and get the first result
+    [  "$1" = "`echo -e "$1\n$2" | sort -V | head -n1`" ]
+}
+verlt() {
+    [ "$1" = "$2" ] && return 1 || verlte $1 $2
+}
+
+closestZeroVersion="$(echo $closestHeadVersion | cut -d '.' -f 1-2).0"
+
+IFS=$'\n'
+for tag in $sortedTags
+do
+    if [[ ! "$tag" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+        # it's not a proper version so ignore
+        continue
+    fi
+
+    # the first less than our closest head should be our latest version
+    if verlt $tag $closestZeroVersion; then
+        echo $tag
+        exit 0
+    fi
+done
+
+echo "did not find an appropriate release tag"
+exit 1

testsuite/find-previous-release-tag.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+set -ueo pipefail
+
+# This script finds the previous tag from the current HEAD position.
+
+closestHeadVersion="$(git describe --tags)"
+
+sortedTags="$(git tag --list --sort -version:refname)"
+
+verlte() {
+    # sort and get the first result
+    [  "$1" = "`echo -e "$1\n$2" | sort -V | head -n1`" ]
+}
+verlt() {
+    [ "$1" = "$2" ] && return 1 || verlte $1 $2
+}
+
+IFS=$'\n'
+for tag in $sortedTags
+do
+    if [[ ! "$tag" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+        # it's not a proper version so ignore
+        continue
+    fi
+
+    # the first less than our closest head should be our latest version
+    if verlt $tag $closestHeadVersion; then
+        echo $tag
+        exit 0
+    fi
+done
+
+echo "did not find an appropriate release tag"
+exit 1