add function to validate money fields

validators/test_validators.py

@@ -1,4 +1,4 @@
-from validators import mandatory, empty, iso_date, valid_iban, valid_bic
+from validators import mandatory, empty, iso_date, valid_iban, valid_bic, valid_money_amount
 
 
 def test_mandatory():
@@ -48,3 +48,12 @@ def test_valid_bic():
     assert valid_bic("PBNKDEFFXXX".split()) == False
 
 
+def test_valid_money_amount():
+    assert valid_money_amount(None) == False
+    assert valid_money_amount("") == False
+    assert valid_money_amount("0,00") == False
+    assert valid_money_amount("13,37") == False
+    assert valid_money_amount("0") == True
+    assert valid_money_amount("0.00") == True
+    assert valid_money_amount("13") == True
+    assert valid_money_amount("13.37") == True

validators/validators.py

@@ -42,3 +42,12 @@ def valid_bic(field: str) -> bool:
         return True
     except ValueError:
         return False
+
+def valid_money_amount(field: str) -> bool:
+    if not field:
+        return False
+    try:
+        float(field)
+        return True
+    except (ValueError, TypeError):
+        return False