diff --git a/tests/src/ParserTest.php b/tests/src/ParserTest.php
index d8f5daf..7f22a69 100644
--- a/tests/src/ParserTest.php
+++ b/tests/src/ParserTest.php
@@ -138,6 +138,16 @@ public function string_to_amount_provider() {
 			[ '.', ',', '-1.250,-', '-1250' ],
 			[ '', '', '123456789', '123456789' ],
 			[ false, false, '123 456 789', '123456789' ],
+			// https://github.com/pronamic/wp-pronamic-pay-gravityforms/issues/40#issuecomment-2106892669
+			[ '.', ',', '2,5 stuks', '2.5' ],
+			[ '.', ',', '2,500 stuks', '2.5' ],
+			[ '.', ',', '2.500 stuks', '2500' ],
+			[ '.', ',', '2.500,50 stuks', '2500.5' ],
+			[ '.', ',', '0,000017 BTC', '1.7e-5' ],
+			[ '.', ',', '0,00037 ETH', '0.00037' ],
+			[ '.', ',', '0,037 ETH', '0.037' ],
+			[ '.', ',', '2,037 ETH', '2.037' ],
+			[ ',', '.', '2,721.51 EUR', '2721.51' ],
 		];
 	}
 }