some cleanup form PR openwebwork#1217 and update test suite

Author: Alex-Jordan

lib/Value/Matrix.pm

@@ -856,8 +856,7 @@ Usage:
 =cut
 
 sub slice {
-	my $self = shift;
-	my ($index, $value) = @_;
+	my ($self, $index, $value) = @_;
 	my @d = $self->dimensions;
 	my $d = scalar(@d);
 	my $w = $d[0];
@@ -867,7 +866,6 @@ sub slice {
 		Value::Error("value must be an integer from 1 to $w")
 			unless ($value == int($value) && $value >= 1 && $value <= $w);
 		return $M->[ $value - 1 ];
-		return $self->make($M->[ $value - 1 ]);
 	} else {
 		my @rows;
 		for (1 .. $w) {
@@ -922,7 +920,7 @@ sub transpose {
 			for my $i (0 .. $#{$cycle} - 1) {
 				$p[ $cycle->[$i] - 1 ] = $p[ $cycle->[ $i + 1 ] - 1 ];
 			}
-			$p[ $cycle->[ $#{$cycle} ] - 1 ] = $tmp;
+			$p[ $cycle->[-1] - 1 ] = $tmp;
 		}
 		%p = map { $_ => $p[ $_ - 1 ] } (1 .. $N);
 	}

t/math_objects/matrix.t

@@ -193,9 +193,8 @@ subtest 'Transpose a Matrix' => sub {
 	is $row->transpose->TeX, $row_trans->TeX, 'Transpose of a degree 1 Matrix.';
 
 	my $C = Matrix([ [ [ 1, 2 ], [ 3, 4 ] ], [ [ 5, 6 ], [ 7, 8 ] ] ]);
-	like dies {
-		$C->transpose;
-	}, qr/Can't transpose \d+-dimensional matrices/, "Can't tranpose a three-d matrix.";
+	my $D = Matrix([ [ [ 1, 3 ], [ 2, 4 ] ], [ [ 5, 7 ], [ 6, 8 ] ] ]);
+	is $C->transpose->TeX, $D->TeX, 'Test the tranpose of a degree 3 tensor.';
 };
 
 subtest 'Extract an element' => sub {