Added info on unattended-upgrades test failure.

tests/test_apt.sh

@@ -6,15 +6,14 @@ set -e
 PATH=/usr/bin:/bin:/usr/sbin:/sbin
 DEBIAN_FRONTEND=noninteractive
 
-echo "Testing apt-get install"
+echo "Testing apt-get install."
 
-echo "Clean repository"
+echo "Clean repository."
 apt-get clean
 
-#Testing if sl package exists and remove it
-
+# Testing if sl package exists and remove it
 if ( dpkg -s sl >/dev/null 2>&1 ); then
-    echo "Removing already installed testing package"
+    echo "Removing already installed testing package."
     apt-get remove -y sl
 fi
 
@@ -25,8 +24,9 @@ apt-get remove -y sl
 
 if [ ! -f /etc/apt/apt.conf.d/20auto-upgrades ]; then
     if [ ! -f /etc/apt/apt.conf.d/50unattended-upgrades ]; then
-        echo "Automatic security updates not enabled"
+        echo "Automatic security updates not enabled."
+        echo "Perhaps the unattended-upgrades package is not installed."
         exit 1
     fi
 fi
-echo "Automatic security updates enabled"
+echo "Automatic security updates enabled."