feat(core/strings): use thousands separator (fixes #2394)

core/.changelog.d/2394.added

@@ -0,0 +1 @@
+Show thousands separator when displaying large amounts.

core/src/apps/bitcoin/sign_tx/layout.py

@@ -190,7 +190,12 @@ async def confirm_total(
     fee_rate_str: str | None = None
 
     if fee_rate >= 0:
-        fee_rate_str = f"({fee_rate:.1f} sat/{'v' if coin.segwit else ''}B)"
+        # Use format_amount to get correct thousands separator -- micropython's built-in
+        # formatting doesn't add thousands sep to floating point numbers.
+        # We multiply by 10 to get a fixed-point integer with one decimal place,
+        # and add 0.5 to round to the nearest integer.
+        fee_rate_formatted = format_amount(int(fee_rate * 10 + 0.5), 1)
+        fee_rate_str = f"({fee_rate_formatted} sat/{'v' if coin.segwit else ''}B)"
 
     await layouts.confirm_total(
         ctx,

core/src/trezor/strings.py

@@ -10,8 +10,14 @@ def format_amount(amount: int, decimals: int) -> str:
         sign = "-"
     else:
         sign = ""
-    d = pow(10, decimals)
-    s = f"{sign}{amount // d}.{amount % d:0{decimals}}".rstrip("0").rstrip(".")
+    d = 10**decimals
+    integer = amount // d
+    decimal = amount % d
+
+    # TODO: bug in mpz: https://github.com/micropython/micropython/issues/8984
+    grouped_integer = f"{integer:,}".lstrip(",")
+
+    s = f"{sign}{grouped_integer}.{decimal:0{decimals}}".rstrip("0").rstrip(".")
     return s
 
 

core/tests/test_apps.bitcoin.signtx.omni.py

@@ -22,8 +22,8 @@ def test_parse(self):
         VECTORS = {
              "6f6d6e69000000000000001f000000002b752ee0": "Simple send of 7.291 USDT",
              "6f6d6e69000000000000001f0000000020c85580": "Simple send of 5.5 USDT",
-             "6f6d6e690000000000000003000000002b752ee0": "Simple send of 729100000 MAID",
-             "6f6d6e690000000000000000000000002b752ee0": "Simple send of 729100000 UNKN",
+             "6f6d6e690000000000000003000000002b752ee0": "Simple send of 729,100,000 MAID",
+             "6f6d6e690000000000000000000000002b752ee0": "Simple send of 729,100,000 UNKN",
              "6f6d6e6901000000": "Unknown transaction",
         }
         for k, v in VECTORS.items():

core/tests/test_apps.ethereum.layout.py

@@ -12,13 +12,13 @@ def test_format(self):
         text = format_ethereum_amount(1, None, 1)
         self.assertEqual(text, '1 Wei ETH')
         text = format_ethereum_amount(1000, None, 1)
-        self.assertEqual(text, '1000 Wei ETH')
+        self.assertEqual(text, '1,000 Wei ETH')
         text = format_ethereum_amount(1000000, None, 1)
-        self.assertEqual(text, '1000000 Wei ETH')
+        self.assertEqual(text, '1,000,000 Wei ETH')
         text = format_ethereum_amount(10000000, None, 1)
-        self.assertEqual(text, '10000000 Wei ETH')
+        self.assertEqual(text, '10,000,000 Wei ETH')
         text = format_ethereum_amount(100000000, None, 1)
-        self.assertEqual(text, '100000000 Wei ETH')
+        self.assertEqual(text, '100,000,000 Wei ETH')
         text = format_ethereum_amount(1000000000, None, 1)
         self.assertEqual(text, '0.000000001 ETH')
         text = format_ethereum_amount(10000000000, None, 1)
@@ -44,7 +44,7 @@ def test_format(self):
         text = format_ethereum_amount(100000000000000000000, None, 1)
         self.assertEqual(text, '100 ETH')
         text = format_ethereum_amount(1000000000000000000000, None, 1)
-        self.assertEqual(text, '1000 ETH')
+        self.assertEqual(text, '1,000 ETH')
 
         text = format_ethereum_amount(1000000000000000000, None, 61)
         self.assertEqual(text, '1 ETC')
@@ -97,7 +97,7 @@ def test_unknown_token(self):
         self.assertEqual(text, '0 Wei UNKN')
         # unknown token has 0 decimals so is always wei
         text = format_ethereum_amount(1000000000000000000, unknown_token, 1)
-        self.assertEqual(text, '1000000000000000000 Wei UNKN')
+        self.assertEqual(text, '1,000,000,000,000,000,000 Wei UNKN')
 
 
 if __name__ == '__main__':

core/tests/test_trezor.strings.py

@@ -4,13 +4,20 @@
 
 
 class TestStrings(unittest.TestCase):
-
     def test_format_amount(self):
         VECTORS = [
             (123456, 3, "123.456"),
             (4242, 7, "0.0004242"),
             (-123456, 3, "-123.456"),
             (-4242, 7, "-0.0004242"),
+            (123, 5, "0.00123"),
+            (100, 5, "0.001"),
+            (123456789, 0, "123,456,789"),
+            (100000000, 5, "1,000"),
+            (100000001, 5, "1,000.00001"),
+            (100001000, 5, "1,000.01"),
+            (-100001000, 5, "-1,000.01"),
+            (123_456_789_123_456_789_123_456_789, 18, "123,456,789.123456789123456789"),
         ]
         for v in VECTORS:
             self.assertEqual(strings.format_amount(v[0], v[1]), v[2])
@@ -151,5 +158,5 @@ def test_format_timestamp(self):
         strings.format_timestamp(1616057224)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()