make main() accept numbers which correspond to testparfiles() list (!70)

* make main() accept numbers which correspond to testparfiles() list

src/main.jl

 const TO = TimerOutput()
 
 
-function testparfiles()
+function get_testparfiles()
   path = normpath(joinpath(@__DIR__, "..", "test", "IntegrationTests", "refs", "testconfig.toml"))
   if !isfile(path)
     error("failed to locate testconfig $path")
   end
   config = TOML.parsefile(path)
   list = sort(collect(keys(config)))
+  return list
+end
+
+function testparfiles()
+  list = get_testparfiles()
   println("Available list of test parameter files:")
-  for l in list
-    println("  - $l")
-  end
+  pretty_table(hcat(1:length(list), list), alignment=[:r,:l], noheader=true)
   println("Use with `main(\"@test/<name>\")`")
 end
 
@@ -25,6 +28,10 @@ function parse_parfile(filename)
     end
     path
   else
+    nr = tryparse(Int64, filename)
+    if !isnothing(nr)
+      return parse_parfile(nr)
+    end
     filename
   end
   if !isfile(path)
@@ -32,6 +39,15 @@ function parse_parfile(filename)
   end
   return abspath(path)
 end
+function parse_parfile(nr::Integer)
+  testpars = get_testparfiles()
+  if !(1 <= nr <= length(testpars))
+    error("there is no test parfile with nr $nr")
+  end
+  parfile = testpars[nr]
+  path = normpath(joinpath(@__DIR__, "..", "test", "IntegrationTests", "refs", parfile, "$parfile.toml"))
+  return abspath(path)
+end
 
 
 """