There is info from Russian Lua FAQ:
Under the module editing window there are two useful fields. In one of them you can enter the name of an existing page and see how the changed version of the module will work on it. The second is the debugger window. There you can enter any line of text on Lua; debugging of the fn function, which is planned to be used in the call
{{#invoke: Module | fn | a1 | a2 | un = ua | a3}}, usually looks like this:=p.fn{args={"a1","a2",["un"]="ua","a3"}} --simplest case =p.fn(mw.getCurrentFrame():newChild{title="dont matter",args={"a1","a2",["un"]="ua","a3"}}) --if the function involves using the methods of the frame object =p.fn(mw.getCurrentFrame():newChild{title="Template:SHA",args={"sha1","sha2",["ASH"]="SAH"}}:newChild{title="Module:Current",args={"a1","a2",["un"]="ua","a3"}}) --if we test the function for application through the template {{SHA| sha1| sha2| ASH= SAH}}, the most accurate way
I think this information will be useful. However, this debugging method doesn’t work for me - the parameters are not passed to the module. Therefore, I do not add this instruction myself.Carn (talk) 08:16, 6 December 2019 (UTC)