diff --git a/tools/config/api_test.go b/tools/config/api_test.go
index 9c830bdef..223a57f3d 100644
--- a/tools/config/api_test.go
+++ b/tools/config/api_test.go
@@ -17,7 +17,8 @@ func TestConfigParsing(t *testing.T) {
 	tdir := t.TempDir()
 	conf_file := filepath.Join(tdir, "a.conf")
 	os.Mkdir(filepath.Join(tdir, "sub"), 0o700)
-	os.WriteFile(conf_file, []byte(`
+	os.WriteFile(conf_file, []byte(
+		`error main
 # ignore me
 a one
 #: other
@@ -29,7 +30,7 @@ globinclude sub/c?.conf
 	os.WriteFile(filepath.Join(tdir, "sub/b.conf"), []byte("incb cool\ninclude a.conf"), 0o600)
 	os.WriteFile(filepath.Join(tdir, "sub/c1.conf"), []byte("inc1 cool"), 0o600)
 	os.WriteFile(filepath.Join(tdir, "sub/c2.conf"), []byte("inc2 cool\nenvinclude ENVINCLUDE"), 0o600)
-	os.WriteFile(filepath.Join(tdir, "sub/c.conf"), []byte("inc notcool"), 0o600)
+	os.WriteFile(filepath.Join(tdir, "sub/c.conf"), []byte("inc notcool\nerror sub"), 0o600)
 
 	var parsed_lines []string
 	pl := func(key, val string) error {
@@ -45,8 +46,17 @@ globinclude sub/c?.conf
 	if err != nil {
 		t.Fatal(err)
 	}
-	diff := cmp.Diff([]string{"a one", "incb cool", "b ", "inc1 cool", "inc2 cool", "env cool", "inc notcool"}, parsed_lines)
+	err = p.ParseOverrides("over one", "over two")
+	diff := cmp.Diff([]string{"a one", "incb cool", "b ", "inc1 cool", "inc2 cool", "env cool", "inc notcool", "over one", "over two"}, parsed_lines)
 	if diff != "" {
 		t.Fatalf("Unexpected parsed config values:\n%s", diff)
 	}
+	bad_lines := []string{}
+	for _, bl := range p.BadLines() {
+		bad_lines = append(bad_lines, fmt.Sprintf("%s: %d", filepath.Base(bl.Src_file), bl.Line_number))
+	}
+	diff = cmp.Diff([]string{"a.conf: 1", "c.conf: 2"}, bad_lines)
+	if diff != "" {
+		t.Fatalf("Unexpected bad lines:\n%s", diff)
+	}
 }