What is the test for determining whether a plaintiff's trial counsel was ineffective because the petitioner's desire to testify was overrode?

We think it would be useful to us in deciding this appeal for the district court to determine, with the assistance of evidence, in affidavit form or otherwise, from the petitioner's trial counsel, and such other evidence as may be available and relevant, the circumstances under which counsel undertook the actions and omissions that the petitioner alleges overrode his desire to testify. More specifically, we hesitate to determine whether counsel's assistance was ineffective without first affording him an opportunity to be heard and to present evidence, in the form of live testimony, affidavits, or briefs. Sparman v. Edwards, 154 F.3d 51, 52 (2d Cir.1998) (per curiam).