diff --git a/tests/repl.sh b/tests/repl.sh
index 995db869c..0e23a98db 100644
--- a/tests/repl.sh
+++ b/tests/repl.sh
@@ -13,6 +13,10 @@ failing = import ./simple-failing.nix
 :log failing
 "
 
+replUndefinedVariable="
+import ./undefined-variable.nix
+"
+
 testRepl () {
     local nixArgs=("$@")
     local replOutput="$(nix repl "${nixArgs[@]}" <<< "$replCmds")"
@@ -22,10 +26,14 @@ testRepl () {
     nix path-info "${nixArgs[@]}" "$outPath"
     # simple.nix prints a PATH during build
     echo "$replOutput" | grep -qs 'PATH=' || fail "nix repl :log doesn't output logs"
-    local replOutput="$(nix repl "${nixArgs[@]}" <<< "$replFailingCmds")"
+    local replOutput="$(nix repl "${nixArgs[@]}" <<< "$replFailingCmds" 2>&1)"
     echo "$replOutput"
     echo "$replOutput" | grep -qs 'This should fail' \
       || fail "nix repl :log doesn't output logs for a failed derivation"
+    local replOutput="$(nix repl --show-trace "${nixArgs[@]}" <<< "$replUndefinedVariable" 2>&1)"
+    echo "$replOutput"
+    echo "$replOutput" | grep -qs "while evaluating the file" \
+      || fail "nix repl --show-trace doesn't show the trace"
 }
 
 # Simple test, try building a drv
diff --git a/tests/undefined-variable.nix b/tests/undefined-variable.nix
new file mode 100644
index 000000000..579985497
--- /dev/null
+++ b/tests/undefined-variable.nix
@@ -0,0 +1 @@
+let f = builtins.toFile "test-file.nix" "asd"; in import f