As noted in a post below, there are a number of Arabic recensions of Testamentum Domini, none published.
However, although unpublished, two were investigated in a 2018 dissertation from Tübingen, Die Kirchenordnung aus dem Testamentum Domini Nostri Jesu Christi nach den Redaktionen der Handschriften Borg. arab. 22 und Petersburg or. 3, the title of which is self-explanatory. This is the work of Andreas Johannes Ellwardt. This renders the versions of Testamentum Domini that these MSS contain, acessible and readable. There is a short introduction (which I admit I have not read yet), the text of the two MSS (or at least the church-order material, the author has left the introductory apocalypse to one side) in parallel columns, and a (German) translation of the Testamentum Domini church order material in Borg. arab. 22, a manuscript employed by Rahmani in his edition of the Syriac. Although I have not read the dissertation in its entirety I have done some sampling on the texts and on what looks like some very helpful annotation.
The author is modest enough to admit that this is far from the last word on the subject, but it is a very significant word nonetheless. I am only sorry it was not available to me when I was working on the text for my English version. If time allows, it may however provide some material for the blog…
The dissertation may be seen at:
https://publikationen.uni-tuebingen.de › handle › Dissertation_Ellwardt