diff --git a/test/runtests.jl b/test/runtests.jl
index 1140eea..49028f8 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -13,11 +13,14 @@ const GROUP = uppercase(
   end,
 )
 
-function istestfile(filename)
-  return isfile(filename) &&
-         endswith(filename, ".jl") &&
-         startswith(basename(filename), "test")
-end
+isjlfile(fn) = isfile(fn) && endswith(fn, ".jl")
+issetupfile(fn) = any(contains("setup"), splitpath(fn))
+
+"match files of the form `**/test_*.jl`, but exclude `**/*setup*/*.jl` and `**/*setup*.jl`"
+istestfile(fn) = isjlfile(fn) && startswith(basename(fn), "test_") && !issetupfile(fn)
+
+"match files of the form `**/*.jl`, but exclude `**/*_notest.jl`, `**/*setup*/*.jl` and `**/*setup*.jl`"
+isexamplefile(fn) = isjlfile(fn) && !endswith(fn, "_notest.jl") && !issetupfile(fn)
 
 @time begin
   # tests in groups based on folder structure
@@ -33,7 +36,7 @@ end
 
   # single files in top folder
   for file in filter(istestfile, readdir(@__DIR__))
-    (file == basename(@__FILE__)) && continue
+    (file == basename(@__FILE__)) && continue # exclude this file to avoid infinite recursion
     @eval @safetestset $file begin
       include($file)
     end
@@ -41,10 +44,9 @@ end
 
   # test examples
   examplepath = joinpath(@__DIR__, "..", "examples")
-  for file in filter(endswith(".jl"), readdir(examplepath; join=true))
-    filename = basename(file)
+  for file in filter(isexamplefile, readdir(examplepath; join=true))
     @eval begin
-      @safetestset $filename begin
+      @safetestset $(basename(file)) begin
         $(Expr(
           :macrocall,
           GlobalRef(Suppressor, Symbol("@suppress")),