fix empty arg assignment

Author: DannyBen

lib/bashly/views/argument/validations.erb

@@ -3,4 +3,4 @@ if [[ -n $(validate_<%= validation_function %> "$1") ]]; then
   printf "<%= strings[:validation_error] %>\n" "<%= name.upcase %> $(validate_<%= validation_function %> "$1")"
   exit 1
 fi
-% end
+% end

lib/bashly/views/command/parse_requirements_case.erb

@@ -2,7 +2,7 @@
 % if args.any?
 % condition = "if"
 % args.each do |arg|
-<%= condition %> [[ ! ${args[<%= arg.name %>]} ]]; then
+<%= condition %> [[ -z ${args[<%= arg.name %>]+x} ]]; then
 <%= arg.render(:validations).indent 2 %>
   args[<%= arg.name %>]=$1
   shift

lib/bashly/views/flag/validations.erb

@@ -3,4 +3,4 @@ if [[ -n $(validate_<%= validation_function %> "$2") ]]; then
   printf "<%= strings[:validation_error] %>\n" "<%= usage_string %> $(validate_<%= validation_function %> "$2")"
   exit 1
 fi
-% end
+% end

spec/approvals/examples/empty-args

@@ -3,15 +3,20 @@ skipped src/initialize.sh (exists)
 skipped src/test_command.sh (exists)
 created ./cli
 run ./cli --help to test your bash script
++ ./cli test a b --flag c
+args:
+- ${args[--flag]} = c
+- ${args[optional_arg]} = b
+- ${args[required_arg]} = a
 + ./cli test ''
-# this file is located in 'src/test_command.sh'
-# code for 'cli test' goes here
-# you can edit it freely and regenerate (it will not be overwritten)
 args:
-- ${args[arg]} = 
-+ ./cli test --flag ''
-# this file is located in 'src/test_command.sh'
-# code for 'cli test' goes here
-# you can edit it freely and regenerate (it will not be overwritten)
+- ${args[required_arg]} = 
++ ./cli test '' --flag ''
+args:
+- ${args[--flag]} = 
+- ${args[required_arg]} = 
++ ./cli test '' '' --flag ''
 args:
 - ${args[--flag]} = 
+- ${args[optional_arg]} = 
+- ${args[required_arg]} =