What is the legal test for validity under the general regulation of trade and commerce power?

Dickson J. there enumerated five possible indicia of validity under the general regulation of trade branch of the trade and commerce power, at p. 47 C.P.R., p. 62 D.L.R., pp. 267-8 S.C.R., pp. 276-7 N.R.: The line of demarcation is clear between measures validly directed at a general regulation of the national economy and those merely aimed at centralized control over a large number of local economic entities. • • • • • In approaching this difficult problem of characterization it is useful to note the remarks of the Chief Justice in MacDonald v. Vapor Canada Ltd., supra, at pp. 25-6 D.L.R., p. 28 C.P.R., p. 165 S.C.R. in which he cites as possible indicia for a valid exercise of the general trade and commerce power the presence of a national regulatory scheme, the oversight of a regulatory agency and a concern with trade in general rather than with an aspect of a particular business. To this list I would add what to my mind would be even stronger indications of valid general regulation of trade and commerce, namely (i) that the provinces jointly or severally would be constitutionally incapable of passing such an enactment, and (ii) that failure to include one or more provinces or localities would jeopardize successful operation in other parts of the country. The above does not purport to be an exhaustive list, nor is the presence of any or all of these indicia necessarily decisive.