test: add td.Smuggle tests

Signed-off-by: Maxime Soulé <btik-git@scoubidou.com>

Author: maxatome

td/td_smuggle_private_test.go

@@ -53,6 +53,9 @@ func TestFieldsPath(t *testing.T) {
 		t.Errorf("Failed:\n       got: %v\n  expected: %v", got, fp)
 	}
 
+	check("[foo][bar]", "foo", "bar")
+	check("[0][foo][bar]", "0", "foo", "bar")
+
 	//
 	// Errors
 	checkErr := func(in, expectedErr string) {

td/td_smuggle_test.go

@@ -745,6 +745,24 @@ func TestSmuggleFieldsPath(t *testing.T) {
 	checkOK(t, x, td.Lax(td.Smuggle("PppA", nil)))
 	checkOK(t, x, td.Smuggle("PppA", td.Nil()))
 
+	checkOK(t, x.Iface, td.Smuggle("[test][1]", 3))
+	checkError(t, x.Iface, td.Smuggle("[unknown][1]", 42),
+		expectedError{
+			Message: mustBe("ran smuggle code with %% as argument"),
+			Path:    mustBe("DATA"),
+			Summary: mustContain(`
+it failed coz: field "[unknown]", "unknown" map key not found`),
+		})
+
+	checkOK(t, x.C.Iface1, td.Smuggle("[0][66][1]", "bar"))
+	checkError(t, x.C.Iface1, td.Smuggle("[42][66][1]", "bar"),
+		expectedError{
+			Message: mustBe("ran smuggle code with %% as argument"),
+			Path:    mustBe("DATA"),
+			Summary: mustContain(`
+it failed coz: field "[42]", 42 is out of slice/array range (len 13)`),
+		})
+
 	//
 	type D struct {
 		Iface any