What is the test for establishing "legitimate ground" in a Habeas corpus application?

In keeping with Pratt v. Nova Scotia (Attorney General), 2020 NSCA 39, at para. 55, the following principles must be followed: 55 The principles that govern are well-known and not controversial. By way of a cursory overview they include: • Habeas corpus is a "non-discretionary" remedy. It must be issued as of right by the provincial superior courts where the requirements are met. • If the applicant proves a deprivation of liberty and raises a legitimate ground to question the legality of the deprivation the matter must proceed to a hearing. • If the applicant has raised such a ground, the onus shifts to the respondent authorities to show the deprivation of liberty was lawful. • The requirement for a legitimate ground has been characterised as "a legitimate doubt" or "some basis" to question the lawfulness of the detention. This requirement is different than actual proof that the detention is unlawful. The legal burden to prove lawfulness rests upon the respondent decision maker. • An interpretation of the test for "legitimate ground" that increases the standard of proof, or imposes technical legal requirements, runs the risk of unduly narrowing the scope of this constitutionally protected remedy. • Thus, when interpreting the legitimate ground requirement attention must be paid to avoid shifting the burden improperly. This is especially so in situations where the applicant claims lack of access to information or reasons concerning their detention. • This interpretation of the content of the applicant's obligation to show "grounds" to question the lawfulness of a decision is consistent with the purpose of the remedy to hold authorities to account for incursions on personal liberty. • A challenge to the fairness of the process may be based on procedural violations of either or both the common law and statute. In determining the fairness of the process, apart from transient or trifling complaints, respondent decision makers are not entitled to deference by the reviewing court. • In short, the rules that govern can be said to favour the prisoner, requiring the respondent decision maker to introduce evidence to justify the deprivation where the prisoner has discharged their evidential burden by establishing a factual context that "bears upon" the legality of the imprisonment. A claim based on no disclosure or reasons for decision can meet that requirement.