[Ubuntu] Migrate tests for common tools to Pester (part 1) (#2288)

* add common tools tests pt1

* fix tests

* fix erlang test

* resolve comments

* minor changes

* remove extra logging

images/linux/scripts/installers/erlang.sh

@@ -4,6 +4,8 @@
 ##  Desc:  Installs erlang
 ################################################################################
 
+source $HELPER_SCRIPTS/invoke-tests.sh
+
 source_list=/etc/apt/sources.list.d/eslerlang.list
 
 # Install Erlang
@@ -17,14 +19,7 @@ wget -q -O rebar3 https://s3.amazonaws.com/rebar3/rebar3
 chmod +x rebar3
 mv rebar3 /usr/local/bin/rebar3
 
-# Run tests to determine that the software installed as expected
-echo "Testing to make sure that script performed as expected, and basic scenarios work"
-for cmd in erl erlc rebar3; do
-    if ! command -v $cmd; then
-        echo "$cmd was not installed or not found on PATH"
-        exit 1
-    fi
-done
+invoke_tests "Tools" "erlang"
 
 # Clean up source list
 rm $source_list