File: test_rna2d.py

package info (click to toggle)
python-cogent 1.4.1-1.2
  • links: PTS, VCS
  • area: non-free
  • in suites: squeeze
  • size: 13,260 kB
  • ctags: 20,087
  • sloc: python: 116,163; ansic: 732; makefile: 74; sh: 9
file content (1074 lines) | stat: -rw-r--r-- 44,673 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
#!/usr/bin/env python
"""Tests for ViennaStructure and related classes.
"""
from cogent.util.unit_test import TestCase, main
from cogent.struct.rna2d import ViennaStructure, Vienna, Pairs,\
    Partners, EmptyPartners, WussStructure, wuss_to_vienna, StructureNode, \
    Stem, classify, PairError

__author__ = "Rob Knight"
__copyright__ = "Copyright 2007-2009, The Cogent Project"
__credits__ = ["Rob Knight", "Sandra Smit"]
__license__ = "GPL"
__version__ = "1.4.1"
__maintainer__ = "Rob Knight"
__email__ = "rob@spot.colorado.edu"
__status__ = "Production"

class RnaAlphabet(object):
    Pairs = {
    ('A','U'): True,    #True vs False for 'always' vs 'sometimes' pairing
    ('C','G'): True,
    ('G','C'): True,
    ('U','A'): True,
    ('G','U'): False,
    ('U','G'): False,
}

class Rna(str):
    Alphabet = RnaAlphabet

class StemTests(TestCase):
    """Tests for the Stem object"""

    def test_init_empty(self):
        """Stem should init ok with no parameters."""
        s = Stem()
        self.assertEqual((s.Start, s.End, s.Length), (None, None, 0))

    def test_init(self):
        """Stem should init with Start, End, and Length"""
        s = Stem(Length=3)
        self.assertEqual((s.Start, s.End, s.Length), (None, None, 3))
        #should set Length to 0 if not supplied and unpaired
        s = Stem(Start=3)
        self.assertEqual((s.Start, s.End, s.Length), (3, None, 0))
        s = Stem(End=3)
        self.assertEqual((s.Start, s.End, s.Length), (None, 3, 0))
        #should set Length to 1 if not supplied and paired
        s = Stem(Start=3, End=5)
        self.assertEqual((s.Start, s.End, s.Length), (3, 5, 1))
        #parameters should be in order Start, End, Length
        #note that you're allowed to initialize an invalid stem, like the
        #following one (can't have 7 pairs between 3 and 5); this is often
        #useful when building up a tree that you plan to renumber().
        s = Stem(3, 5, 7)
        self.assertEqual((s.Start, s.End, s.Length), (3, 5, 7))
        #not allowed more than 3 parameters
        self.assertRaises(TypeError, Stem, 1, 2, 3, 4)
    
    def test_len(self):
        """Stem len() should return self.Length"""
        s = Stem()
        self.assertEqual(len(s), 0)
        s.Length = 5
        self.assertEqual(len(s), 5)
        s.Length = None
        self.assertRaises(TypeError, len, s)

    def test_getitem(self):
        """Stem getitem should return a Stem object for the ith pair in the stem"""
        s = Stem()
        self.assertRaises(IndexError, s.__getitem__, 0)
        s.Start = 5
        s.End = 8
        s.Length = 1
        pairs = list(s)
        self.assertEqual(pairs, [Stem(5, 8, 1)])
        s.Length = 2
        pairs = list(s)
        self.assertEqual(pairs, [Stem(5,8,1),Stem(6,7,1)])
        #WARNING: Stem will not complain when iterating over an invalid helix,
        #as per the one below
        s.Length = 5
        pairs = list(s)
        self.assertEqual(pairs, [Stem(5,8,1),Stem(6,7,1),Stem(7,6,1),\
            Stem(8,5,1), Stem(9,4,1)])

    def test_cmp(self):
        """Stems should compare equal when the data is the same"""
        self.assertEqual(Stem(1,2,3), Stem(1,2,3))
        self.assertNotEqual(Stem(1,2,5), Stem(1,2,3))

        a = Stem(1, 10, 2)
        b = Stem(2, 8, 1)
        c = Stem(15, 20, 2)
        l = [c, b, a]
        l.sort()
        self.assertEqual(l, [a,b,c])

    def test_extract(self):
        """Stems extract should return a list of 'pairs' from a sequence"""
        seq = 'UGAGAUUUUCU'
        s = Stem(1, 10, 3)
        self.assertEqual(s.extract(seq), [('G','U'),('A','C'),('G','U')])
        s = Stem(0, 1)
        self.assertEqual(s.extract(seq), [('U','G')])
        #should put in None if either position hasn't been specified
        s = Stem(5)
        self.assertEqual(s.extract(seq), [('U', None)])
        s = Stem()
        self.assertEqual(s.extract(seq), [(None, None)])
        #should raise IndexError if the stem contains bases outside the seq
        s = Stem(50, 60, 5)
        self.assertRaises(IndexError, s.extract, seq)

    def test_hash(self):
        """Stems hash should allow use as dict keys if unchanged"""
        #WARNING: if you change the Stem after putting it in a dict, all bets
        #are off as to behavior. Don't do it!
        s = Stem(1, 5, 2)
        t = Stem(1, 5, 2)
        u = Stem(2, 4, 6)
        v = Stem(2, 4, 6)
        w = Stem(2, 4, 4)
        d = {}

        assert s is not t
        
        for i in (s, t, u, v, w):
            if i in d:
                d[i] += 1
            else:
                d[i] = 1

        self.assertEqual(len(d), 3)
        self.assertEqual(d[Stem(1, 5, 2)], 2)
        self.assertEqual(d[Stem(2, 4, 6)], 2)
        self.assertEqual(d[Stem(2, 4, 4)], 1)
        assert Stem(1,5) not in d

    def test_str(self):
        """Stem str should print Start, End and Length as a tuple"""
        self.assertEqual(str(Stem()), '(None,None,0)')
        self.assertEqual(str(Stem(3)), '(3,None,0)')
        self.assertEqual(str(Stem(3,4)), '(3,4,1)')
        self.assertEqual(str(Stem(3,4,5)), '(3,4,5)')

    def test_nonzero(self):
        """Stem nonzero should return True if paired (length > 0)"""
        assert not Stem()
        assert not Stem(1)
        assert Stem(7, 10)
        assert Stem(1, 7, 1)
        assert Stem(2, 8, 3)
        #go strictly by length; don't check if data is invalid
        assert Stem(0, 0)
        assert Stem(5, None, 10)
        assert not Stem(5, 7, -1)
        
class PartnersTests(TestCase):
    """Tests for Partners object"""

    def test_init(self):
        """Partners should init with empty list and stay free of conflicts"""
        self.assertEqual(Partners([]),[])
        empty = Partners([None]*6)
        self.assertEqual(empty,[None,None,None,None,None,None])
        self.assertRaises(ValueError,empty.__setitem__,2,2) 
        empty[2] = 3
        self.assertEqual(empty,[None,None,3,2,None,None])
        empty[3] = 1
        self.assertEqual(empty,[None,3,None,1,None,None])
        empty[3] = 5
        self.assertEqual(empty,[None,None,None,5,None,3])
        empty[1] = None
        self.assertEqual(empty,[None,None,None,5,None,3])
    
    def test_toPairs(self):
        """Partners toPairs() should return a Pairs object"""
        p = Partners([None,3,None,1,5,4])
        self.assertEqualItems(p.toPairs(),[(1,3),(4,5)])
        assert isinstance(p.toPairs(),Pairs)
        self.assertEqual(Partners([None]*10).toPairs(),[])

    def test_not_implemented(self):
        """Partners not_implemented should raise error for 'naughty' methods"""
        p = Partners([None,3,1,5,4])
        self.assertRaises(NotImplementedError,p.pop)
        self.assertRaises(NotImplementedError,p.sort)
        self.assertRaises(NotImplementedError,p.__delitem__,3)
        
class PairsTests(TestCase):
    """Tests for Pairs object"""

    def setUp(self):
        """Pairs SetUp method for all tests"""
        self.Empty = Pairs([])
        self.OneList = Pairs([[1,2]])
        self.OneTuple = Pairs([(1,2)])
        self.MoreLists = Pairs([[2,4],[3,9],[6,36],[7,49]])
        self.MoreTuples = Pairs([(2,4),(3,9),(6,36),(7,49)])
        self.MulNoOverlap = Pairs([(1,10),(2,9),(3,7),(4,12)])
        self.MulOverlap = Pairs([(1,2),(2,3)])
        self.Doubles = Pairs([[1,2],[1,2],[2,3],[1,3]])
        self.Undirected = Pairs([(2,1),(6,4),(1,7),(8,3)])
        self.UndirectedNone = Pairs([(5,None),(None,3)])
        self.UndirectedDouble = Pairs([(2,1),(1,2)])
    
        self.NoPseudo = Pairs([(1,20),(2,19),(3,7),(4,6),(10,15),(11,14)])
        self.NoPseudo2 = Pairs([(1,3),(4,6)])
        #((.(.)).)
        self.p0 = Pairs([(0,6),(1,5),(3,8)])
        #(.((..(.).).))
        self.p1 = Pairs([(0,9),(2,12),(3,10),(5,7)])
        #((.(.(.).)).)
        self.p2 = Pairs([(0,10),(1,9),(3,12),(5,7)])
        #((.((.(.)).).))
        self.p3 = Pairs([(0,9),(1,8),(3,14),(4,13),(6,11)])
        #(.(((.((.))).)).(((.((((..))).)))).)
        self.p4 = Pairs([(0,35),(2,11),(3,10),(4,9),(6,14),(7,13),(16,28),\
            (17,27),(18,26),(20,33),(21,32),(22,31),(23,30)])
        #(.((.).))
        self.p5 = Pairs([(0,5),(2,8),(3,7)])
        self.p6 = Pairs([(0,19),(2,6),(3,5),(8,14),(9,13),(10,12),\
            (16,22),(17,21)])
        self.p7 = Pairs([(0,20),(2,6),(3,5),(8,14),(9,10),(11,16),(12,15),\
            (17,23),(18,22)])

         
    def test_init(self):
        """Pairs should initalize with both lists and tuples"""
        self.assertEqual(self.Empty,[])
        self.assertEqual(self.OneList,[[1,2]])
        self.assertEqual(self.OneTuple,[(1,2)])
        self.assertEqual(self.MulNoOverlap,[(1,10),(2,9),(3,7),(4,12)])
        self.assertEqual(self.MulOverlap,[(1,2),(2,3)])

    def test_toPartners(self):
        """Pairs toPartners() should return a Partners object"""
        a = Pairs([(1,5),(3,4),(6,9),(7,8)]) #normal
        b = Pairs([(0,4),(2,6)]) #pseudoknot
        c = Pairs([(1,6),(3,6),(4,5)]) #conflict

        self.assertEqual(a.toPartners(10),[None,5,None,4,3,1,9,8,7,6])
        self.assertEqual(a.toPartners(13,3),\
        [None,None,None,None,8,None,7,6,4,12,11,10,9])
        assert isinstance(a.toPartners(10),Partners)
        self.assertEqual(b.toPartners(7),[4,None,6,None,0,None,2])
        self.assertRaises(ValueError,c.toPartners,7)
        self.assertEqual(c.toPartners(7,strict=False),[None,None,None,6,5,4,3])

        #raises an error when try to insert something at non-existing indices
        self.assertRaises(IndexError,c.toPartners,0)

    def test_toVienna(self):
        """Pairs toVienna() should return a ViennaStructure if possible"""
        a = Pairs([(1,5),(3,4),(6,9),(7,8)]) #normal
        b = Pairs([(0,4),(2,6)]) #pseudoknot
        c = Pairs([(1,6),(3,6),(4,5)]) #conflict
        d = Pairs([(1,6),(3,None)])
        e = Pairs([(1,9),(8,2),(7,3)]) #not directed
        f = Pairs([(1,6),(2,5),(10,15),(14,11)]) # not directed

        self.assertEqual(a.toVienna(10),'.(.())(())')
        self.assertEqual(a.toVienna(13,offset=3),'....(.())(())')
        
        self.assertRaises(PairError,b.toVienna,7) #pseudoknot NOT accepted
        self.assertRaises(Exception,b.toVienna,7) #old test for exception
        self.assertRaises(ValueError,c.toVienna,7)
        
        #pairs containging None are being skipped
        self.assertEquals(d.toVienna(7),'.(....)')
        
        #raises error when trying to insert at non-existing indices
        self.assertRaises(IndexError,a.toVienna,3)

        self.assertEqual(Pairs().toVienna(3),'...')
        
        #test when parsing in the sequence
        self.assertEqual(a.toVienna('ACGUAGCUAG'),'.(.())(())')
        self.assertEqual(a.toVienna(Rna('AACCGGUUAGCUA'), offset=3),\
            '....(.())(())')
       
        self.assertEqual(e.toVienna(10),'.(((...)))')
        self.assertEqual(f.toVienna(20),'.((..))...((..))....')

    def test_tuples(self):
        """Pairs tuples() should transform the elements of list to tuples"""
        x = Pairs([])
        x.tuples()
        assert x == []
        
        x = Pairs([[1,2],[3,4]])
        x.tuples()
        assert x == [(1,2),(3,4)]
        
        x = Pairs([(1,2),(3,4)])
        x.tuples()
        assert x == [(1,2),(3,4)]
        assert x != [[1,2],[3,4]]

    def test_unique(self):
        """Pairs unique() should remove double occurences of certain tuples"""
        self.assertEqual(self.Empty.unique(),[])
        self.assertEqual(self.MoreTuples.unique(),self.MoreTuples)
        self.assertEqual(self.Doubles.unique(),Pairs([(1,2),(2,3),(1,3)]))

    def test_directed(self):
        """Pairs directed() should change all pairs so that a<b in (a,b)"""
        self.assertEqual(self.Empty.directed(),[])
        res = self.Undirected.directed()
        res.sort()
        self.assertEqual(res,Pairs([(1,2),(1,7),(3,8),(4,6)]))
        res = self.UndirectedNone.directed()
        self.assertEqual(res,Pairs([]))
        res = self.UndirectedDouble.directed()
        self.assertEqual(res,Pairs([(1,2)]))

    def test_symmetric(self):
        """Pairs symmetric() should add (down,up) for each (up,down)"""
        self.assertEqual(self.Empty.symmetric(),[])
        self.assertEqualItems(self.OneTuple.symmetric(),[(2,1),(1,2)])
        self.assertEqualItems(Pairs([(1,2),(1,2)]).symmetric(),[(1,2),(2,1)])
        self.assertEqualItems(Pairs([(1,2),(3,4)]).symmetric(),\
        [(1,2),(2,1),(3,4),(4,3)])
        self.assertEqualItems(Pairs([(1,None)]).symmetric(),[])

    def test_paired(self):
        """Pairs paired() should omit all pairs containing None"""
        self.assertEqual(self.Empty.paired(),[])
        self.assertEqual(Pairs([(1,2),(2,None),(None,3),(None,None)]).paired()\
        ,[(1,2)])

    def test_hasConflicts(self):
        """Pairs hasConflicts() should return True if there are conflicts"""
        assert not self.Empty.hasConflicts()
        assert not Pairs([(1,2),(3,4)]).hasConflicts()
        assert Pairs([(1,2),(2,3)]).hasConflicts()
        assert Pairs([(1,2),(2,None)]).hasConflicts()

    def test_mismatches(self):
        """Pairs mismatches() should return #pairs that can't be formed"""
        # with plain string
        self.assertEqual(Pairs([(0,1)]).mismatches('AC',{}),1)
        self.assertEqual(Pairs([(0,1)]).mismatches('AC',{('A','C'):None}),0)
        self.assertEqual(Pairs([(0,1)]).mismatches('AC',{('A','G'):None}),1)
        self.assertEqual(Pairs([(0,1),(2,3),(3,1)]).\
        mismatches('ACGU',{('A','U'):None}),3)

        # using sequence with alphabet
        sequence = Rna('ACGUA')
        self.assertEqual(Pairs([(0,1),(0,4),(0,3)]).mismatches(sequence),2)

    def test_hasPseudoknots(self):
        """Pairs hasPseudoknots() should return True if there's a pseudoknot"""
                
        assert not self.NoPseudo.hasPseudoknots()
        assert not self.NoPseudo2.hasPseudoknots()
        #add tests for ((.))() etc
        assert self.p0.hasPseudoknots()
        assert self.p1.hasPseudoknots() 
        assert self.p2.hasPseudoknots()
        assert self.p3.hasPseudoknots()
        assert self.p4.hasPseudoknots()
        assert self.p5.hasPseudoknots()
        assert self.p6.hasPseudoknots()
        assert self.p7.hasPseudoknots()

        
class StructureStringInitTests(TestCase):
    """Tests for initializing structures"""
    
    def setUp(self):
        self.Struct = ViennaStructure
        self.Empty = ''
        self.NoPairs = '.....'
        self.OneHelix = '((((()))))'
        self.ManyHelices = '(..(((...)).((.(((((..))).)))..((((..))))))...)'
        self.Ends = '..(.)..'   #has trailing bases at ends
        self.Internal = '(((...)))..(()).' #has internal non-nested region
        self.TooManyOpen = '(((...))..'
        self.TooManyClosed = '((...)))..'
        self.Invalid = 'fdjklgfj'
    
    def test_init_empty(self):
        """StructureString initialization should accept an empty string"""
        self.assertEqual(self.Empty, str(self.Struct(self.Empty)))
        
    def test_init_no_pairs(self):
        """StructureString should allow a structure with no pairs"""
        self.assertEqual(self.NoPairs, str(self.Struct(self.NoPairs)))

    def test_init_one_helix(self):
        """StructureString should allow a structure with one helix"""
        self.assertEqual(self.OneHelix, str(self.Struct(self.OneHelix)))

    def test_init_long_nested(self):
        """StructureString should accept long structure w/ many nested pairs"""
        self.assertEqual(self.ManyHelices,str(self.Struct(self.ManyHelices)))

    def test_init_too_many_pairs_opened(self):
        """StructureString should raise IndexError if too many open pairs"""
        self.assertRaises(IndexError, self.Struct, self.TooManyOpen)

    def test_init_too_few_pairs_opened(self):
        """StructureString should raise IndexError if too few open pairs"""
        self.assertRaises(IndexError, self.Struct, self.TooManyClosed)

    def test_init_invalid_string(self):
        """StructureString should raise ValueError if invalid chars"""
        self.assertRaises(ValueError, self.Struct, self.Invalid)


class WussStructureInitTests(StructureStringInitTests):
    """Test for initializing WussStructures"""
    def setUp(self):
        self.Struct = WussStructure
        self.Empty = ''
        self.NoPairs = '__--_'
        self.OneHelix = '[{(<()>)}]'
        self.ManyHelices = '<,,(({___})~((:((({{__}}),))),,<<[(__)]>>)):::>'
        self.TooManyOpen = '{<[___]>::'
        self.TooManyClosed = '<<___>>>::'
        self.Invalid = '__!<><>'


class StructureStringTests(TestCase):
    """Test that StructureString methods and properties work.
    
    By default tested on a ViennaStructure. These tests should
    work for every StructureString.
    """
    Struct = ViennaStructure

    def setUp(self):
        """SetUp for all StructureString tests"""
        self.Energy1 = 0.0
        self.Energy2 = -1e-02
        self.NoPairsStr = '.....'
        self.NoPairs = self.Struct('.....',self.Energy1)
        self.OneHelixStr = '((((()))))'
        self.OneHelix = self.Struct('((((()))))',self.Energy2)
        self.TwoHelixStr = '((.))(()).'
        self.TwoHelix = self.Struct('((.))(()).',self.Energy1)
        self.ThreeHelixStr = '(((((..))..(((..)))..)))'
        self.ThreeHelix = self.Struct('(((((..))..(((..)))..)))')
        self.EmptyStr = ''
        self.ManyHelicesStr = '(..(((...)).((.(((((..))).)))..((((..))))))...)'
        self.EndsStr = '..(.)..'   #has trailing bases at ends
        self.InternalStr = '(((...)))..(()).' #has internal non-nested region
    
    def test_len(self):
        """StructureString len() should match structure length"""
        self.assertEqual(len(self.TwoHelix), 10)
        #Do you want the init possible with Vienna() for empty str???
        self.assertEqual(len(Vienna('')), 0)

    def test_getitem(self):
        """StructureString struct[index] should return char at index in struct"""
        self.assertEqual(self.NoPairs[0], self.NoPairsStr[0])  #dot
        self.assertEqual(self.OneHelix[0], self.OneHelixStr[0]) #close pair
        #negative index, end
        self.assertEqual(self.OneHelix[-1], self.OneHelixStr[-1])
        #middle of sequence
        self.assertEqual(self.TwoHelix[4], self.TwoHelixStr[4]) 
                
    def test_getslice(self):
        """StructureString struct[a:b] should return slice from a to b"""
        self.assertEqual(self.OneHelix[0:3], self.OneHelixStr[0:3])
        self.assertEqual(self.OneHelix[0:0], self.OneHelixStr[0:0])
        self.assertEqual(self.OneHelix[:], self.OneHelixStr[:])
        self.assertEqual(self.OneHelix[4:7], self.OneHelixStr[4:7])
        self.assertEqual(self.OneHelix[5:], self.OneHelixStr[5:])
        
    def test_str(self):
        """StructureString str() should print structure and energy, if known"""
        self.assertEqual(str(self.NoPairs),  '..... (0.0)')
        self.assertEqual(str(self.OneHelix), '((((())))) (-0.01)')
        self.assertEqual(str(self.TwoHelix), '((.))(()). (0.0)')
        self.assertEqual(str(self.ThreeHelix), '(((((..))..(((..)))..)))')
        
    def test_toPartners(self):
        """StructureString toPartners() should return Partners object"""
        self.assertEqual(self.NoPairs.toPartners(), [None]*5)
        self.assertEqual(self.OneHelix.toPartners(),[9,8,7,6,5,4,3,2,1,0])
        self.assertEqual(self.TwoHelix.toPartners(),\
        [4,3,None,1,0,8,7,6,5,None])
        self.assertEqual(self.ThreeHelix.toPartners(),[23,22,21,8,7,None,\
        None,4,3,None,None,18,17,16,None,None,13,12,11,None,None,2,1,0])

    def test_toPairs(self):
        """StructureString toPairs() should return Pairs object"""
        self.assertEqual(self.NoPairs.toPairs(), [])
        self.assertEqualItems(self.OneHelix.toPairs(), \
        [(0,9),(1,8),(2,7),(3,6),(4,5)])
        self.assertEqualItems(self.TwoHelix.toPairs(), \
        [(0,4),(1,3),(5,8),(6,7)])
        self.assertEqualItems(self.ThreeHelix.toPairs(), \
        [(0,23),(1,22),(2,21),(3,8),(4,7),(11,18),(12,17),(13,16)])
    
    def test_toTree(self):
        """StructureString toTree should produce correct tree"""
        for struct in [self.EmptyStr, self.NoPairsStr, self.OneHelixStr, \
            self.ManyHelicesStr, self.EndsStr, self.InternalStr]:
            self.assertEqual(str(self.Struct(struct).toTree()), struct)

        test = self.Struct(self.ManyHelicesStr).toTree()
        n = test[0]
        self.assertEqual(n.Start, 0)
        self.assertEqual(n.End, 46)
        n = test[0][2][0][0][1]
        self.assertEqual(n.Start, 7)
        self.assertEqual(n.End, None)
        n = test[0][2][1]
        self.assertEqual(n.Start, 11)
        self.assertEqual(n.End, None)
        n = test[0][2][2][0][1][0][0][0][0][1]
        self.assertEqual(n.Start, 21)
        self.assertEqual(n.End, None)

        test = self.Struct(self.InternalStr).toTree()
        self.assertEqual([i.Start for i in test], [0, 9, 10, 11, 15])
        self.assertEqual([i.End for i in test], [8, None, None, 14, None])

    
class WussStructureTests(StructureStringTests):
    """Test that WussStructure methods and properties work"""
    def setUp(self):
        """Define three standard structures: note differences in whitespace
        and number formatting"""
        self.Struct = WussStructure
        super(WussStructureTests,self).setUp()
        self.WussNoPairs = WussStructure('.-_,~:')
        self.WussOneHelix = WussStructure('[-{<(__)-->}]',-0.01)
        self.WussTwoHelix = WussStructure('{[.]}(<>).',1.11)
        self.WussThreeHelix = WussStructure('::(<<({__}),,([(__)])-->>)')
        self.WussPseudo = WussStructure('<<__AA>>_aa::')
        
    def test_wuss_toPairs(self):
        """WussStructure toPairs() should return a valid Pairs object"""
        self.assertEqual(self.WussNoPairs.toPairs(),[])
        self.assertEqualItems(self.WussOneHelix.toPairs(),\
        [(0,12),(2,11),(3,10),(4,7)])
        self.assertEqualItems(self.WussTwoHelix.toPairs(),\
        [(0,4),(1,3),(5,8),(6,7)])
        self.assertEqualItems(self.WussThreeHelix.toPairs(),\
        [(2,25),(3,24),(4,23),(5,10),(6,9),(13,20),(14,19),(15,18)])
        self.assertEqualItems(self.WussPseudo.toPairs(),\
        [(0,7),(1,6)])
    
    def test_wuss_toPartners(self):
        """WussStructure toPartners() should return valid Partners object"""
        self.assertEqual(self.WussNoPairs.toPartners(),[None]*6)
        self.assertEqualItems(self.WussThreeHelix.toPartners(),\
        [None,None,25,24,23,10,9,None,None,6,5,None,None,20,19,\
        18,None,None,15,14,13,None,None,4,3,2])
        self.assertEqualItems(self.WussPseudo.toPartners(),\
        [7,6,None,None,None,None,1,0,None,None,None,None,None])


class Rna2dTests(TestCase):

    def test_Vienna(self):
        """Vienna should initalize from several formats"""
        self.NoPairs = Vienna('.......... (0.0)')
        self.OneHelix = Vienna('((((()))))    (-1e-02)')
        self.TwoHelix = Vienna('((.))(()). \t(1.11)')
        self.ThreeHelix = Vienna('(((((..))..(((..)))..)))')
        self.GivenEnergy = Vienna('((.))',0.1)
        self.TwoEnergies = Vienna('((.)) (4.6)',2.1)
        
        self.assertEqual(self.NoPairs, '..........')
        self.assertEqual(self.NoPairs.Energy, 0.0)
        self.assertEqual(self.OneHelix, '((((()))))')
        self.assertEqual(self.OneHelix.Energy, -1e-2)
        self.assertEqual(self.TwoHelix, '((.))(()).')
        self.assertEqual(self.TwoHelix.Energy, 1.11)
        self.assertEqual(self.ThreeHelix, '(((((..))..(((..)))..)))')
        self.assertEqual(self.ThreeHelix.Energy, None)
        self.assertEqual(self.GivenEnergy.Energy,0.1)
        self.assertEqual(self.TwoEnergies.Energy,2.1)

    
    def test_EmptyPartners(self):
        """EmptyPartners should return list of 'None's of given length"""
        self.assertEqual(EmptyPartners(0),[])
        self.assertEqual(EmptyPartners(1),[None])
        self.assertEqual(EmptyPartners(10),[None]*10)

    
    def test_wuss_to_vienna(self):
        """wuss_to_vienna() should transform Wuss into Vienna"""
        empty = WussStructure('.....')
        normal = WussStructure('[.{[<...}}}}')
        pseudo = WussStructure('[..AA..]..aa')
        self.assertEqual(wuss_to_vienna(normal),'(.(((...))))')
        self.assertEqual(wuss_to_vienna(empty),'.....')
        self.assertEqual(wuss_to_vienna(pseudo),'(......)....')

    def test_classify(self):
        """classify() should classify valid structures correctly"""
        Empty = '' 
        NoPairs = '.....'
        OneHelix = '((((()))))'
        ManyHelices = '(..(((...)).((.(((((..))).)))..((((..))))))...)'
        Ends = '..(.)..'
        FirstEnd = '..((()))'
        LastEnd = '((..((.))))...'
        Internal = '(((...)))..((.)).'
        #following structure is from p 25 of Eddy's WUSS description manual
        Eddy = '..((((.(((...)))...((.((....))..)).)).))'

        structs = [Empty, NoPairs, OneHelix, ManyHelices, Ends, \
            FirstEnd, LastEnd, Internal, Eddy]

        EmptyResult = '' 
        NoPairsResult = 'EEEEE'
        OneHelixResult = 'SSSSSSSSSS'
        ManyHelicesResult = 'SBBSSSLLLSSJSSBSSSSSLLSSSBSSSJJSSSSLLSSSSSSBBBS'
        EndsResult = 'EESLSEE'
        FirstEndResult = 'EESSSSSS'
        LastEndResult = 'SSBBSSLSSSSEEE'
        InternalResult = 'SSSLLLSSSFFSSLSSE'
        #following structure is from p 25 of Eddy's WUSS description manual
        Eddy = 'EESSSSJSSSLLLSSSJJJSSBSSLLLLSSBBSSJSSBSS'

        results = [EmptyResult, NoPairsResult, OneHelixResult, 
            ManyHelicesResult, EndsResult, FirstEndResult, LastEndResult, 
            InternalResult, Eddy]
      
        for s, r in zip(structs, results):
            c = classify(s)
            self.assertEqual(classify(s), r)

        long_struct = ".((((((((((((((.((((((..((((.....)))))))))).))..))))))))))))....(((.((((.((((((((......((((((.((..(((((((....)))).)))..))))))))...))))))))...........(((((.(..(((((((((......((((((((((((.........))))))))))))....))))).))))..)..)))))..(((((((((((((((((((......(((((((((((((((((((((((((((((((...(((.......((((((((........)))))))).......)))...))))))))))))))))))))))))))))))).((((........(((((((((((((((((((...))))))))))))))))))).......)))).....((((((((((((((((((((((((((((((.(((...))).)))))))))))))))))))))))...........))))))).))))))))))))))))))).....)))).)))......"
        
        #compare standalone method with classification from tree
        c = classify(long_struct)
        d = ViennaStructure(long_struct).toTree().classify()
        self.assertEqual(c,d)

        #Error is raised when trying to classify invalid structures
        invalid_structure = '(((..)).))))(...)(...'
        self.assertRaises(IndexError, classify, invalid_structure)
                    

class ViennaNodeTests(TestCase):
    """Tests of the ViennaNode class."""
    def setUp(self):
        """Instantiate some standard ViennaNodes."""
        self.EmptyStr = '' 
        self.NoPairsStr = '.....'
        self.OneHelixStr = '((((()))))'
        self.ManyHelicesStr = '(..(((...)).((.(((((..))).)))..((((..))))))...)'
        self.EndsStr = '..(.)..'
        self.FirstEndStr = '..((()))'
        self.LastEndStr = '((..((.))))...'
        self.InternalStr = '(((...)))..((.)).'
        #following structure is from p 25 of Eddy's WUSS description manual
        self.EddyStr = '..((((.(((...)))...((.((....))..)).)).))'
        
        #add in the tree versions by deleting trailing 'Str'
        for s in self.__dict__.keys():
            if s.endswith('Str'):
                self.__dict__[s[:-3]] = \
                    ViennaStructure(self.__dict__[s]).toTree()

    def test_str(self):
        """ViennaNode str should return Vienna-format string"""
        for s in [self.EmptyStr, self.NoPairsStr, self.OneHelixStr,
            self.ManyHelicesStr, self.EndsStr, self.InternalStr]:
            self.assertEqual(str(ViennaStructure(s).toTree()), s)

        #test with multiple-base helix in a node
        r = StructureNode()
        r.append(StructureNode())
        r.append(StructureNode(Data=Stem(1,7,5)))
        r[1].append(StructureNode())
        r.append(StructureNode())
        r.append(StructureNode())
        r.renumber()
        self.assertEqual(str(r), '.(((((.)))))..')

    def test_classify(self):
        """ViennaNode classify should return correct classification string"""
        self.assertEqual(self.Empty.classify(), '')
        self.assertEqual(self.NoPairs.classify(), 'EEEEE')
        self.assertEqual(self.OneHelix.classify(), 'SSSSSSSSSS')
        self.assertEqual(self.ManyHelices.classify(), \
            'SBBSSSLLLSSJSSBSSSSSLLSSSBSSSJJSSSSLLSSSSSSBBBS')
        self.assertEqual(self.Ends.classify(), 'EESLSEE')
        self.assertEqual(self.FirstEnd.classify(), 'EESSSSSS')
        self.assertEqual(self.LastEnd.classify(), 'SSBBSSLSSSSEEE')
        self.assertEqual(self.Internal.classify(), 'SSSLLLSSSFFSSLSSE')
        self.assertEqual(self.Eddy.classify(), \
            'EESSSSJSSSLLLSSSJJJSSBSSLLLLSSBBSSJSSBSS')

    def test_renumber(self):
        """ViennaNode renumber should assign correct numbers to nodes"""
        #should have no effect on empty structure
        se = self.Empty
        self.assertEqual(se.renumber(5), 5)
        self.assertEqual((se.Start, se.End, se.Length), (None, None, 0))
        #with no pairs, should number consecutively
        sn = self.NoPairs
        self.assertEqual(sn.renumber(5), 10)
        self.assertEqual([i.Start for i in sn], [5, 6, 7, 8, 9])
        self.assertEqual([i.End for i in sn], [None]*5)
        self.assertEqual([i.Length for i in sn], [0]*5)
        #spot checks on a complex structure
        sm = self.ManyHelices
        self.assertEqual(sm.renumber(5), 52)
        s0 = sm[0]
        self.assertEqual((s0.Start, s0.End, s0.Length), (5, 51, 1))
        s5 = sm[0][2][2][0]
        self.assertEqual(len(s5), 2)
        self.assertEqual((s5.Start, s5.End, s5.Length), (18, 33, 1))
        s6 = s5[0]
        self.assertEqual((s6.Start, s6.End, s6.Length), (19,None,0))
        #test with some helices of different lengths
        root = StructureNode()
        root.extend([StructureNode() for i in range(3)])
        root.insert(1, StructureNode(Data=Stem(3, 7, 5)))
        root.insert(3, StructureNode(Data=Stem(6,2,2)))
        root.append(StructureNode())
        self.assertEqual(root.renumber(0), 18)
        self.assertEqual(len(root), 6)
        curr = root[0]
        self.assertEqual((curr.Start,curr.End,curr.Length), (0, None, 0))
        curr = root[1]
        self.assertEqual((curr.Start, curr.End, curr.Length), (1, 10, 5))
        curr = root[2]
        self.assertEqual((curr.Start, curr.End, curr.Length), (11, None, 0))
        curr = root[3]
        self.assertEqual((curr.Start, curr.End, curr.Length), (12, 15, 2))
        curr = root[4]
        self.assertEqual((curr.Start, curr.End, curr.Length), (16, None, 0))
        curr = root[5]
        self.assertEqual((curr.Start, curr.End, curr.Length), (17, None, 0))

    def test_unpair(self):
        """StructureNode unpair should break a base pair and add correct nodes"""
        i = self.Internal
        self.assertEqual(i[0].unpair(), True)
        self.assertEqual(str(i), '.((...))...((.)).')
        e = self.Ends
        self.assertEqual(e[0].unpair(), False)
        self.assertEqual(str(e), self.EndsStr)
        o = self.OneHelix
        self.assertEqual(o[0].unpair(), True)
        self.assertEqual(str(o), '.(((()))).')
        self.assertEqual(o[1][0][0].unpair(), True)
        self.assertEqual(str(o), '.((.().)).')
        self.assertEqual(o[1].unpair(), True)
        self.assertEqual(str(o), '..(.().)..')
        self.assertEqual(o[2][1].unpair(), True)
        self.assertEqual(str(o), '..(....)..')
        self.assertEqual(o[2].unpair(), True)
        self.assertEqual(str(o), '..........')
        #test with multiple bases in helix
        r = StructureNode()
        r.append(StructureNode(Data=Stem(0,0, 5)))
        r.renumber()
        self.assertEqual(str(r), '((((()))))')
        self.assertEqual(r[0].unpair(), True)
        self.assertEqual(str(r), '.(((()))).')

    def test_pairBefore(self):
        """StructureNode pairBefore should make a pair before the current node"""
        #shouldn't be able to make any pairs if everything is paired already
        o = self.OneHelix
        for i in o:
            self.assertEqual(i.pairBefore(), False)
            
        n = self.NoPairs
        #shouldn't be able to pair at the start...
        self.assertEqual(n[0].pairBefore(), False)
        #...or at the end...
        self.assertEqual(n[-1].pairBefore(), False)
        #...but should work OK in the middle
        self.assertEqual(n[1].pairBefore(), True)
        self.assertEqual(str(n), '(.)..')

        e = self.Ends
        self.assertEqual(e[2].pairBefore(), True)
        self.assertEqual(e[1].pairBefore(), True)
        self.assertEqual(str(e), '(((.)))')
        self.assertEqual((e[0].Start, e[0].End, e[0].Length), (0,6,1))

    def test_pairAfter(self):
        """StructureNode pairAfter should create pairs after a node"""
        n = self.NoPairs
        self.assertEqual(n.pairAfter(), True)
        self.assertEqual(str(n), '(...)')
        self.assertEqual(n[0].pairAfter(), True)
        self.assertEqual(str(n), '((.))')
        self.assertEqual(n[0][0].pairAfter(), False)
        self.assertEqual(str(n), '((.))')
        curr = n[0][0]
        #check that child is correct
        self.assertEqual(len(curr), 1)
        self.assertEqual((curr[0].Start, curr[0].End, curr[0].Length), \
            (2,None,0))
        #check that pair is correct
        self.assertEqual((curr.Start, curr.End, curr.Length), (1,3,1))

        m = self.ManyHelices
        n = m[0][2][0][0]
        self.assertEqual(n.pairAfter(), True)
        self.assertEqual(str(m), \
            '(..((((.))).((.(((((..))).)))..((((..))))))...)')
        self.assertEqual(n[0].pairAfter(), False)
    
    def test_pairChildren(self):
        """StructureNode PairChildren should make the correct pairs"""
        n = ViennaStructure('.....').toTree()   #same as self.NoPairs
        self.assertEqual(n.pairChildren(0, 4), True)
        self.assertEqual(str(n), '(...)')
        n = ViennaStructure('.....').toTree()   #same as self.NoPairs
        self.assertEqual(n.pairChildren(1, 4), True)
        self.assertEqual(str(n), '.(..)')
        n = ViennaStructure('.....').toTree()   #same as self.NoPairs
        #can't pair same object
        self.assertEqual(n.pairChildren(1, 1), False)
        self.assertEqual(str(n), '.....')
        self.assertEqual(n.pairChildren(1, -1), True)
        self.assertEqual(str(n), '.(..)')
        #can't pair something already paired
        self.assertEqual(n.pairChildren(0,1), False)
        #IndexError if out of range
        self.assertRaises(IndexError, n.pairChildren, 0, 5)
        n.append(StructureNode())
        n.append(StructureNode())
        n.renumber()
        self.assertEqual(str(n), '.(..)..')
        self.assertEqual(n.pairChildren(0, -2), True)
        self.assertEqual(str(n), '((..)).')

    def test_expand(self):
        """StructureNode expand should extend helices."""
        s = StructureNode(Data=(Stem(1, 10, 3)))
        s.append(StructureNode())
        #need to make a root node for consistency
        r = StructureNode()
        r.append(s)
        self.assertEqual(str(s), '(((.)))')
        s.expand()
        self.assertEqual(str(s), '(((.)))')
        self.assertEqual((s.Start, s.End, s.Length), (1, 10, 1))
        n = s[0]
        self.assertEqual((n.Start, n.End, n.Length), (2, 9, 1))
        n = s[0][0]
        self.assertEqual((n.Start, n.End, n.Length), (3, 8, 1))
        n = s[0][0][0]
        self.assertEqual((n.Start, n.End, n.Length), (None, None, 0))
        s.renumber()
        self.assertEqual((s.Start, s.End, s.Length), (0, 6, 1))
        n = s[0]
        self.assertEqual((n.Start, n.End, n.Length), (1, 5, 1))
        n = s[0][0]
        self.assertEqual((n.Start, n.End, n.Length), (2, 4, 1))
        n = s[0][0][0]
        self.assertEqual((n.Start, n.End, n.Length), (3, None, 0))
        #check that it's not recursive
        s[0][0].append(StructureNode(Data=Stem(20, 24, 2)))
        s.expand()
        n = s[0][0][-1]
        self.assertEqual((n.Start, n.End, n.Length), (20, 24, 2))
        n.expand()
        self.assertEqual((n.Start, n.End, n.Length), (20, 24, 1))
        n = n[0]
        self.assertEqual((n.Start, n.End, n.Length), (21, 23, 1))
        
    def test_expandAll(self):
        """StructureNode expandAll should act recursively"""
        r = StructureNode()
        r.append(StructureNode(Data=Stem(0, 6, 4)))
        r.append(StructureNode(Data=Stem(0, 6, 3)))
        r.append(StructureNode())
        r[0].append(StructureNode())
        r[0].append(StructureNode(Data=Stem(0,6,2)))
        r[0][-1].append(StructureNode())
        r.renumber()
        self.assertEqual(str(r), '((((.((.))))))((())).')
        r.expandAll()
        self.assertEqual(str(r), '((((.((.))))))((())).')
        expected_nodes = [
            (None, None, 0),
            (0, 13, 1),
            (1, 12, 1),
            (2, 11, 1),
            (3, 10, 1),
            (4, None, 0),
            (5, 9, 1),
            (6, 8, 1),
            (7, None, 0),
            (14, 19, 1),
            (15, 18, 1),
            (16, 17, 1),
            (20, None, 0),
        ]
        for obs, exp in zip(r.traverse(), expected_nodes):
            self.assertEqual((obs.Start, obs.End, obs.Length), exp)

    def test_collapse(self):
        """StructureNode collapse should collapse consecutive pairs from self"""
        one = ViennaStructure('(.)').toTree()
        self.assertEqual(one.collapse(), False)
        self.assertEqual(str(one), '(.)')
        two = ViennaStructure('((.))').toTree()
        #can't collapse root node
        self.assertEqual(two.collapse(), False)
        #should be able to collapse next node
        self.assertEqual(two[0].collapse(), True)
        self.assertEqual((two[0].Start, two[0].End, two[0].Length), (0,4,2))
        self.assertEqual(str(two), '((.))')
        three = ViennaStructure('(((...)))..').toTree()
        self.assertEqual(three[0].collapse(), True)
        self.assertEqual((three[0].Start, three[0].End, three[0].Length), \
            (0,8,3))
        self.assertEqual(str(three), '(((...)))..')
        self.assertEqual(three[0].collapse(), False)
        self.assertEqual(three[-1].collapse(), False)

        oh = self.OneHelix
        self.assertEqual(oh[0].collapse(), True)
        self.assertEqual(str(oh), '((((()))))')
        
    def test_collapseAll(self):
        """StructureNode collapseAll should collapse consecutive pairs"""
        for s in [self.Empty, self.NoPairs, self.OneHelix, self.ManyHelices,\
            self.Ends, self.FirstEnd, self.LastEnd, self.Internal, self.Eddy]:
            before = str(s)
            s.collapseAll()
            after = str(s)
            self.assertEqual(after, before)

        oh = self.OneHelix[0]
        self.assertEqual((oh.Start, oh.End, oh.Length), (0,9,5))
        m_obs = self.ManyHelices.traverse()
        m_exp = [
            (None, None, 0),
            (0, 46, 1),
            (1, None, 0),
            (2, None, 0),
            (3, 42, 1),
            (4, 10, 2),
            (6, None, 0),
            (7, None, 0),
            (8, None, 0),
            (11, None, 0),
            (12, 41, 1),
            (13, 28, 1),
            (14, None, 0),
            (15, 27, 2),
            (17, 24, 3),
            (20, None, 0),
            (21, None, 0),
            (25, None, 0),
            (29, None, 0),
            (30, None, 0),
            (31, 40, 4),
            (35, None, 0),
            (36, None, 0),
            (43, None, 0),
            (44, None, 0),
            (45, None, 0),
            (46, None, 0),
        ]
        for obs, exp in zip([(i.Start, i.End, i.Length) for i in m_obs], m_exp):
            self.assertEqual(obs, exp)

    def test_breakBadPairs(self):
        """StructureNode breakBadPairs should eliminate mispaired bases."""
        oh_str = ViennaStructure(self.OneHelixStr)
        #no change if all pairs valid
        oh = oh_str.toTree()
        oh.breakBadPairs(Rna('CCCCCGGGGG'))
        self.assertEqual(str(oh), str(oh_str))
        #break everything if all pairs invalid
        oh.breakBadPairs(Rna('CCCCCAAAAA'))
        self.assertEqual(str(oh), '..........')
        #break a single pair
        oh = oh_str.toTree()
        oh.breakBadPairs(Rna('GCCCCGGGGG'))
        self.assertEqual(str(oh), '.(((()))).')
        #break two pairs
        oh = oh_str.toTree()
        oh.breakBadPairs(Rna('GCCCCCGGGG'))
        self.assertEqual(str(oh), '.(((..))).')
        #break internal pairs
        oh = oh_str.toTree()
        oh.breakBadPairs(Rna('GCCGCGGGGG'))
        self.assertEqual(str(oh), '.((.().)).')
        #repeat with multiple independent helices
        th_str = ViennaStructure('((.)).((.))')
        th = th_str.toTree()
        th.breakBadPairs(Rna('CCUGGCUUCGG'))
        self.assertEqual(str(th), th_str)
        th.breakBadPairs(Rna('CGUAGCAGUUU'))
        self.assertEqual(str(th), '(...).((.))')
        th = th_str.toTree()
        th.breakBadPairs(Rna('UUUUUUUUUUU'))
        self.assertEqual(str(th), '...........')

    def test_extendHelix(self):
        """StructureNode extendHelix should extend the helix as far as possible
        """
        #single paired node is root[4]
        op_str = ViennaStructure('....(......)...')
        op = op_str.toTree()
        #can't extend if base pairs not allowed
        op[4].extendHelix(Rna('AAAAAAAAAAAAAAA'))
        self.assertEqual(str(op), op_str)
        #should extend a pair 5'
        op[4].extendHelix(Rna('AAACCAAAAAAGGAA'))
        self.assertEqual(str(op), '...((......))..')
        #should extend multiple pairs 5'
        op = op_str.toTree()
        op[4].extendHelix(Rna('CCCCCUUUUUUGGGG'))
        self.assertEqual(str(op), '.((((......))))')
        #should extend a pair 3', but must leave > 2-base loop
        op = op_str.toTree()
        op[4].extendHelix(Rna('AAAACCCCGGGGAAA'))
        self.assertEqual(str(op), '....((....))...')
        op[4][0].insert(1, StructureNode(Data=Stem(Start=1,End=1,Length=1)))
        op.renumber()
        self.assertEqual(str(op), '....((.()...))...')
        op[4][0].extendHelix(Rna( 'AAAACCCUACGGGGAAA'))
        self.assertEqual(str(op), '....(((()..)))...')
        #should extend a pair in both directions if possible
        op = op_str.toTree()
        op[4].extendHelix(Rna('AAACCCAAAAGGGAA'))
        self.assertEqual(str(op), '...(((....)))..')
        
    def test_extendHelices(self):
        """StructureNode extendHelices should extend all helices"""
        e = ViennaStructure('........')
        t = e.toTree()
        t.extendHelices(Rna('CCCCCCCCCC'))
        self.assertEqual(str(t), e)
        #no pairs if sequence can't form them
        s = ViennaStructure('(.....(...)..)...((.....))...')
        r =             Rna('AAAAAAAAAAAAAAAAAAAAAAAAAAAAA')
        t = s.toTree()
        t.extendHelices(r)
        self.assertEqual(str(t), s)
        #should be able to extend a single helix
        s = ViennaStructure('(.....(...)..)...((.....))...')
        r =             Rna('CAAAAACAAAGAAGCCCCCCCAGGGGGGG')
        t = s.toTree()
        t.extendHelices(r)
        self.assertEqual(str(t), '(.....(...)..)((((((...))))))')
        #should be able to extend multiple helices
        s = ViennaStructure('(.....(...)..)...((.....))...')
        r =             Rna('AAAAACCCAGGGUUCCCCCAUAAAGGGAA')
        t = s.toTree()
        t.extendHelices(r)
        self.assertEqual(str(t), '((...((...))))..(((.....)))..')
        
    def test_fitSeq(self):
        """StructureNode fitSeq should adjust structure to match sequence"""
        #this is just a minimal test, since we know that both breakBadPairs()
        #and extendHelices() work fine with more extensive tests.
        s = ViennaStructure('..(((.....)))......(((.....)))...')
        r = Rna(            'UCCCCACUGAGGGGUUUGGGGGGUUUUCGCCCU')
        t = s.toTree()
        t.fitSeq(r)
        self.assertEqual(str(t), '.((((.....))))...(((.((...)).))).')

#run the test suites if invoked as a script from the command line
if __name__ == "__main__":
    main()