#18 Modeller / Aligner dry run tests look for exe

[Raik Gruenberg]

The Modeller and Aligner dry run tests, which should not depend on modeller or t-coffee being available, raise an error if modeller or t-coffee are not installed.

e.g. run::
cd biskit/Biskit
python test -e pvm exe long

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ERROR: Mod.Modeller dry run
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Traceback (most recent call last):
File "/home/raik/data/py/Biskit/Mod/Modeller.py", line 615, in test_modeller
self.runmodeller(run=0)
File "/home/raik/data/py/Biskit/Mod/Modeller.py", line 591, in runmodeller
ending_model=2 )
File "/home/raik/data/py/Biskit/Mod/Modeller.py", line 141, in __init__
**kw)
File "/home/raik/data/py/Biskit/Executor.py", line 308, in __init__
self.exe.validate()
File "/home/raik/data/py/Biskit/ExeConfig.py", line 228, in validate
raise ExeConfigError, str(why) + ' Check %s!' % self.dat
ExeConfigError: binary modeller not found. Check /home/raik/data/py/biskit/external/defaults/exe_modeller.dat!

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Ran 77 tests in 112.131s