1 files changed, 110 insertions, 0 deletions
diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py
new file mode 100644
index 0000000..cf8c094
--- /dev/null
+++ b/Lib/test/test_float.py
@@ -0,0 +1,110 @@
+
+import unittest, struct
+from test import test_support
+
+class FormatFunctionsTestCase(unittest.TestCase):
+
+    def setUp(self):
+        self.save_formats = {'double':float.__getformat__('double'),
+                             'float':float.__getformat__('float')}
+
+    def tearDown(self):
+        float.__setformat__('double', self.save_formats['double'])
+        float.__setformat__('float', self.save_formats['float'])
+
+    def test_getformat(self):
+        self.assert_(float.__getformat__('double') in
+                     ['unknown', 'IEEE, big-endian', 'IEEE, little-endian'])
+        self.assert_(float.__getformat__('float') in
+                     ['unknown', 'IEEE, big-endian', 'IEEE, little-endian'])
+        self.assertRaises(ValueError, float.__getformat__, 'chicken')
+        self.assertRaises(TypeError, float.__getformat__, 1)
+
+    def test_setformat(self):
+        for t in 'double', 'float':
+            float.__setformat__(t, 'unknown')
+            if self.save_formats[t] == 'IEEE, big-endian':
+                self.assertRaises(ValueError, float.__setformat__,
+                                  t, 'IEEE, little-endian')
+            elif self.save_formats[t] == 'IEEE, little-endian':
+                self.assertRaises(ValueError, float.__setformat__,
+                                  t, 'IEEE, big-endian')
+            else:
+                self.assertRaises(ValueError, float.__setformat__,
+                                  t, 'IEEE, big-endian')
+                self.assertRaises(ValueError, float.__setformat__,
+                                  t, 'IEEE, little-endian')
+            self.assertRaises(ValueError, float.__setformat__,
+                              t, 'chicken')
+        self.assertRaises(ValueError, float.__setformat__,
+                          'chicken', 'unknown')
+
+BE_DOUBLE_INF = '\x7f\xf0\x00\x00\x00\x00\x00\x00'
+LE_DOUBLE_INF = ''.join(reversed(BE_DOUBLE_INF))
+BE_DOUBLE_NAN = '\x7f\xf8\x00\x00\x00\x00\x00\x00'
+LE_DOUBLE_NAN = ''.join(reversed(BE_DOUBLE_NAN))
+
+BE_FLOAT_INF = '\x7f\x80\x00\x00'
+LE_FLOAT_INF = ''.join(reversed(BE_FLOAT_INF))
+BE_FLOAT_NAN = '\x7f\xc0\x00\x00'
+LE_FLOAT_NAN = ''.join(reversed(BE_FLOAT_NAN))
+
+# on non-IEEE platforms, attempting to unpack a bit pattern
+# representing an infinity or a NaN should raise an exception.
+
+class UnknownFormatTestCase(unittest.TestCase):
+    def setUp(self):
+        self.save_formats = {'double':float.__getformat__('double'),
+                             'float':float.__getformat__('float')}
+        float.__setformat__('double', 'unknown')
+        float.__setformat__('float', 'unknown')
+        
+    def tearDown(self):
+        float.__setformat__('double', self.save_formats['double'])
+        float.__setformat__('float', self.save_formats['float'])
+
+    def test_double_specials_dont_unpack(self):
+        for fmt, data in [('>d', BE_DOUBLE_INF),
+                          ('>d', BE_DOUBLE_NAN),
+                          ('<d', LE_DOUBLE_INF),
+                          ('<d', LE_DOUBLE_NAN)]:
+            self.assertRaises(ValueError, struct.unpack, fmt, data)
+
+    def test_float_specials_dont_unpack(self):
+        for fmt, data in [('>f', BE_FLOAT_INF),
+                          ('>f', BE_FLOAT_NAN),
+                          ('<f', LE_FLOAT_INF),
+                          ('<f', LE_FLOAT_NAN)]:
+            self.assertRaises(ValueError, struct.unpack, fmt, data)
+
+
+# on an IEEE platform, all we guarantee is that bit patterns
+# representing infinities or NaNs do not raise an exception; all else
+# is accident (today).
+
+class IEEEFormatTestCase(unittest.TestCase):
+    if float.__getformat__("double").startswith("IEEE"):
+        def test_double_specials_do_unpack(self):
+            for fmt, data in [('>d', BE_DOUBLE_INF),
+                              ('>d', BE_DOUBLE_NAN),
+                              ('<d', LE_DOUBLE_INF),
+                              ('<d', LE_DOUBLE_NAN)]:
+                struct.unpack(fmt, data)
+
+    if float.__getformat__("float").startswith("IEEE"):
+        def test_float_specials_do_unpack(self):
+            for fmt, data in [('>f', BE_FLOAT_INF),
+                              ('>f', BE_FLOAT_NAN),
+                              ('<f', LE_FLOAT_INF),
+                              ('<f', LE_FLOAT_NAN)]:
+                struct.unpack(fmt, data)
+
+
+def test_main():
+    test_support.run_unittest(
+        FormatFunctionsTestCase,
+        UnknownFormatTestCase,
+        IEEEFormatTestCase)
+
+if __name__ == '__main__':
+    test_main()