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c:\python24\lib \ test \ test_fpformat.py



0001 '''
0002    Tests for fpformat module
0003    Nick Mathewson
0004 '''
0005 from test.test_support import run_unittest
0006 import unittest
0007 from fpformat import fix, sci, NotANumber
0008 
0009 StringType = type('')
0010 
0011 # Test the old and obsolescent fpformat module.
0012 #
0013 # (It's obsolescent because fix(n,d) == "%.*f"%(d,n) and
0014 #                           sci(n,d) == "%.*e"%(d,n)
0015 #  for all reasonable numeric n and d, except that sci gives 3 exponent
0016 #  digits instead of 2.
0017 #
0018 # Differences only occur for unreasonable n and d.    <.2 wink>)
0019 
0020 class FpformatTest(unittest.TestCase):
0021 
0022     def checkFix(self, n, digits):
0023         result = fix(n, digits)
0024         if isinstance(n, StringType):
0025             n = repr(n)
0026         expected = "%.*f" % (digits, float(n))
0027 
0028         self.assertEquals(result, expected)
0029 
0030     def checkSci(self, n, digits):
0031         result = sci(n, digits)
0032         if isinstance(n, StringType):
0033             n = repr(n)
0034         expected = "%.*e" % (digits, float(n))
0035         # add the extra 0 if needed
0036         num, exp = expected.split("e")
0037         if len(exp) < 4:
0038             exp = exp[0] + "0" + exp[1:]
0039         expected = "%se%s" % (num, exp)
0040 
0041         self.assertEquals(result, expected)
0042 
0043     def test_basic_cases(self):
0044         self.assertEquals(fix(100.0/3, 3), '33.333')
0045         self.assertEquals(sci(100.0/3, 3), '3.333e+001')
0046 
0047     def test_reasonable_values(self):
0048         for d in range(7):
0049             for val in (1000.0/3, 1000, 1000.0, .002, 1.0/3, 1e10):
0050                 for realVal in (val, 1.0/val, -val, -1.0/val):
0051                     self.checkFix(realVal, d)
0052                     self.checkSci(realVal, d)
0053 
0054     def test_failing_values(self):
0055         # Now for 'unreasonable n and d'
0056         self.assertEquals(fix(1.0, 1000), '1.'+('0'*1000))
0057         self.assertEquals(sci("1"+('0'*1000), 0), '1e+1000')
0058 
0059         # This behavior is inconsistent.  sci raises an exception; fix doesn't.
0060         yacht = "Throatwobbler Mangrove"
0061         self.assertEquals(fix(yacht, 10), yacht)
0062         try:
0063             sci(yacht, 10)
0064         except NotANumber:
0065             pass
0066         else:
0067             self.fail("No exception on non-numeric sci")
0068 
0069 
0070 def test_main():
0071     run_unittest(FpformatTest)
0072 
0073 
0074 if __name__ == "__main__":
0075     test_main()
0076 

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