Handled @mgedmin's original concern about high-precision numbers (in contrast to really small numbers).

2 files changed, 25 insertions, 1 deletions

diff --git a/src/zope/i18n/format.py b/src/zope/i18n/format.py
index 055869e..494d09c 100644
--- a/src/zope/i18n/format.py
+++ b/src/zope/i18n/format.py
@@ -31,6 +31,9 @@ from ._compat import _u
 PY3 = sys.version_info[0] == 3
 if PY3:
     unicode = str
+    NATIVE_NUMBER_TYPES = (int, float)
+else:
+    NATIVE_NUMBER_TYPES = (int, float, long)
 
 def roundHalfUp(n):
     """Works like round() in python2.x
@@ -372,7 +375,12 @@ class NumberFormat(object):
         else:
             bin_pattern = bin_pattern[1]
 
-        strobj = str(obj)
+        if isinstance(obj, NATIVE_NUMBER_TYPES):
+            # repr() handles high-precision numbers correctly in
+            # Python 2 and 3. str() is only correct in Python 3.
+            strobj = repr(obj)
+        else:
+            strobj = str(obj)
         if 'e' in strobj:
             # Str(obj) # returned scientific representation of a number (e.g.
             # 1e-7). We can't rely on str() to format fraction.
diff --git a/src/zope/i18n/tests/test_formats.py b/src/zope/i18n/tests/test_formats.py
index 9f48fdb..ce235c3 100644
--- a/src/zope/i18n/tests/test_formats.py
+++ b/src/zope/i18n/tests/test_formats.py
@@ -1180,6 +1180,22 @@ class TestNumberFormat(TestCase):
         self.assertEqual(self.format.format(
             -1e-7, '(#0.00#####);(-#0.00#####)'), '(-0.0000001)')
         self.assertEqual(self.format.format(1e-9, '(#0.00###)'), '(0.00)')
+        self.assertEqual(self.format.format(1e-9, '(#0.00###)'), '(0.00)')
+
+    def testFormatHighPrecisionNumbers(self):
+        self.assertEqual(self.format.format(
+            1+1e-7, '(#0.00#####);(-#0.00#####)'), '(1.0000001)')
+        self.assertEqual(self.format.format(
+            1+1e-7, '(#0.00###)'), '(1.00000)')
+        self.assertEqual(self.format.format(
+            1+1e-9, '(#0.00#######);(-#0.00#######)'), '(1.000000001)')
+        self.assertEqual(self.format.format(
+            1+1e-9, '(#0.00###)'), '(1.00000)')
+        self.assertEqual(self.format.format(
+            1+1e-12, '(#0.00##########);(-#0.00##########)'),
+            '(1.000000000001)')
+        self.assertEqual(self.format.format(
+            1+1e-12, '(#0.00###)'), '(1.00000)')
 
     def testNoRounding(self):
         # Witout Rounding