sympy/sympy — pull request #7830 by pbrady (2014-08-06 15:40:29+00:00)
Title: Fix test_elliptic test failure

* On master
```bash
PYTHONHASHSEED=1421912842 bin/test sympy/mpmath/tests/test_elliptic.py -k test_sn_cn_dn_identities --seed 1970464
============================= test process starts ==============================
executable: /home/ptb/miniconda3/bin/python (3.4.1-final-0) [CPython]
architecture: 64-bit
cache: yes
ground types: gmpy 1.17
random seed: 1970464
hash randomization: on (PYTHONHASHSEED=1421912842)

sympy/mpmath/tests/test_elliptic.py[1] F [FAIL]

________________________________________________________________________________
_________ sympy/mpmath/tests/test_elliptic.py:test_sn_cn_dn_identities _________
File "/home/ptb/gitrepos/sympy/sympy/mpmath/tests/test_elliptic.py", line 556, in test_sn_cn_dn_identities
assert(equality.ae(0))
AssertionError

============= tests finished: 0 passed, 1 failed, in 0.10 seconds ==============
DO *NOT* COMMIT!
```

Following the guidance in #5821, add epsilon to ensure values are correct to within 1e-99 rather than exact

* this PR
```bash
PYTHONHASHSEED=1421912842 bin/test sympy/mpmath/tests/test_elliptic.py -k test_sn_cn_dn_identities --seed 1970464
============================= test process starts ==============================
executable: /home/ptb/miniconda3/bin/python (3.4.1-final-0) [CPython]
architecture: 64-bit
cache: yes
ground types: gmpy 1.17
random seed: 1970464
hash randomization: on (PYTHONHASHSEED=1421912842)

sympy/mpmath/tests/test_elliptic.py[1] . [OK]

================== tests finished: 1 passed, in 0.11 seconds ===================
```