Fix the unit test that attempts to construct a NumberWithUnits with no number.

Author: drgrice1

lib/Parser/Legacy/NumberWithUnits.pm

@@ -363,7 +363,7 @@ sub makeValue {
 	my $value   = shift;
 	my %options = (context => $self->context, @_);
 	my $num     = Value::makeValue($value, %options);
-	return bless $num, 'Parser::Legacy::FormulaWithUnits' if $num->classMatch('Formula');
+	return bless $num, 'Parser::Legacy::FormulaWithUnits' if defined $num && $num->classMatch('Formula');
 	Value::Error("A number with units must be a constant, not %s", lc(Value::showClass($num)))
 		unless Value::isReal($num);
 	bless $num, $options{class};

t/units/basic_parser.t

@@ -95,12 +95,8 @@ subtest 'Test error handling' => sub {
 		qr/Unrecognizable unit: \|$fake\|/,
 		"No unit '$fake' defined in Units file"
 	);
-	like(dies { NumberWithUnits(1) }, qr/You must provide units for your number/, 'No unit given');
-	like(
-		dies { NumberWithUnits('J') },
-		qr/You must provide units for your number/,
-		'No value given, wants 2 arguments'
-	);
+	like(dies { NumberWithUnits(1) },   qr/You must provide units for your number/,         'No unit given');
+	like(dies { NumberWithUnits('J') }, qr/A number with units must be a constant, not ''/, 'No value given');
 };
 
 subtest 'Check parsing of arguments' => sub {