function validate( node ) {
		var tokens;
		var source;
		var close;
		var open;
		var arg;

		if ( node.callee.name === 'require' ) {
			source = context.getSourceCode();
			tokens = source.getTokens( node );
			open = tokens[ 1 ];
			close = tokens[ tokens.length - 1 ];
			arg = node.arguments[ 0 ];

			// Check space after opening parenthesis:
			if ( source.getText().slice( open.range[1], arg.range[0] ) !== ' ' ) {
				report( node, 'There should be exactly one space after the opening parenthesis in require calls.', [ open.range[1], arg.range[0] ] );
			}

			// Check space before closing parenthesis:
			if ( source.getText().slice( arg.range[1], close.range[0] ) !== ' ' ) {
				report( node, 'There should be exactly one space before the closing parenthesis in require calls.', [ arg.range[1], close.range[0] ] );
			}
		}
	}
Checks whether require path has correct spacing.

@private
@param {ASTNode} node - node to examine