Here is an interesting published decision from ACCA in United States v. Pleasant.
The case has a warning, and a reminder of what we often tell clients about testifying. In this case the issue being whether or not the testimony is helpful or hurts, and as ACCA considers:
When an accused testifies on his own behalf, he does so at his own peril, risking that he might fill in gaps or provide affirmative evidence contributing to or resulting in his conviction.
Contrary to appellant’s assignment of error, this court finds the evidence both legally and factually sufficient to affirm appellant’s conviction for larceny. This conclusion is not only supported by the evidence presented in the government’s case, but also by the testimony given by appellant in his defense, where he stated that he did not intend to steal military property. On this point, appellant’s testimony was
not credible and, as such, is affirmative evidence of his guilt.