diff --git a/testes/lush/config.lua b/testes/lush/config.lua
index 4a36ddec..3e8ca048 100644
--- a/testes/lush/config.lua
+++ b/testes/lush/config.lua
@@ -48,7 +48,7 @@ end
 do
   local tmpdir = tmpbase .. "_t1"
   mkdir(tmpdir .. "/lush")
-  writefile(tmpdir .. "/lush/config", '_LUSH_TEST_MARKER = 42\n')
+  writefile(tmpdir .. "/lush/config.lua", '_LUSH_TEST_MARKER = 42\n')
 
   local out = run_with_config(tmpdir, "print(_LUSH_TEST_MARKER)")
   assert(out:find("42"), "config file should set global: " .. out)
@@ -79,7 +79,7 @@ end
 do
   local tmpdir = tmpbase .. "_t3"
   mkdir(tmpdir .. "/lush/config.d")
-  writefile(tmpdir .. "/lush/config", '_LUSH_SEQ = "M"\n')
+  writefile(tmpdir .. "/lush/config.lua", '_LUSH_SEQ = "M"\n')
   writefile(tmpdir .. "/lush/config.d/01.lua",
     '_LUSH_SEQ = _LUSH_SEQ .. "D"\n')
 
@@ -94,7 +94,7 @@ end
 do
   local tmpdir = tmpbase .. "_t4"
   mkdir(tmpdir .. "/lush")
-  writefile(tmpdir .. "/lush/config", '_LUSH_SUPPRESSED = true\n')
+  writefile(tmpdir .. "/lush/config.lua", '_LUSH_SUPPRESSED = true\n')
 
   local out = run_with_config_E(tmpdir, "print(_LUSH_SUPPRESSED)")
   assert(out:find("nil"), "-E should suppress config: " .. out)
@@ -139,7 +139,7 @@ end
 do
   local tmpdir = tmpbase .. "_t7"
   mkdir(tmpdir .. "/lush")
-  writefile(tmpdir .. "/lush/config", 'error("config boom")\n')
+  writefile(tmpdir .. "/lush/config.lua", 'error("config boom")\n')
 
   local out = run_with_config(tmpdir, "print(99)")
   assert(out:find("99"), "config error should be non-fatal: " .. out)
diff --git a/testes/lush/prompt.lua b/testes/lush/prompt.lua
index cc13dfb5..f793bae1 100644
--- a/testes/lush/prompt.lua
+++ b/testes/lush/prompt.lua
@@ -26,7 +26,7 @@ local function run_lua(input, config_content)
   local tmpdir = tmpbase .. "_run"
   mkdir(tmpdir .. "/lush")
   if config_content then
-    writefile(tmpdir .. "/lush/config", config_content)
+    writefile(tmpdir .. "/lush/config.lua", config_content)
   end
   local cmd = string.format(
     'printf "%%s\\n" %s | XDG_CONFIG_HOME="%s" ./lua -i 2>&1',