pybsddb 4.3.1, adds support for DB.set_bt_compare database btree comparison

functions written in python.

contributed by <frederic.gobry@epfl.ch>

2 files changed, 216 insertions, 0 deletions

diff --git a/Lib/bsddb/test/test_all.py b/Lib/bsddb/test/test_all.py
index 7b1bf3d..701bdfe 100644
--- a/Lib/bsddb/test/test_all.py
+++ b/Lib/bsddb/test/test_all.py
@@ -50,6 +50,7 @@ def suite():
         'test_associate',
         'test_basics',
         'test_compat',
+        'test_compare',
         'test_dbobj',
         'test_dbshelve',
         'test_dbtables',
diff --git a/Lib/bsddb/test/test_compare.py b/Lib/bsddb/test/test_compare.py
new file mode 100644
index 0000000..f8b2312
--- /dev/null
+++ b/Lib/bsddb/test/test_compare.py
@@ -0,0 +1,215 @@
+"""
+TestCases for python DB Btree key comparison function.
+"""
+
+import sys, os
+import test_all
+
+import unittest
+from bsddb3 import db
+
+def lexical_cmp (db, left, right):
+  return cmp (left, right)
+
+def lowercase_cmp(db, left, right):
+  return cmp (left.lower(), right.lower())
+
+def make_reverse_comparator (cmp):
+  def reverse (db, left, right, delegate=cmp):
+    return - delegate (db, left, right)
+  return reverse
+
+_expected_lexical_test_data = ['', 'CCCP', 'a', 'aaa', 'b', 'c', 'cccce', 'ccccf']
+_expected_lowercase_test_data = ['', 'a', 'aaa', 'b', 'c', 'CC', 'cccce', 'ccccf', 'CCCP']
+
+class ComparatorTests (unittest.TestCase):
+  def comparator_test_helper (self, comparator, expected_data):
+    data = expected_data[:]
+    data.sort (lambda l, r, cmp=comparator: cmp (None, l, r))
+    self.failUnless (data == expected_data,
+                     "comparator `%s' is not right: %s vs. %s"
+                     % (comparator, expected_data, data))
+  def test_lexical_comparator (self):
+    self.comparator_test_helper (lexical_cmp, _expected_lexical_test_data)
+  def test_reverse_lexical_comparator (self):
+    rev = _expected_lexical_test_data[:]
+    rev.reverse ()
+    self.comparator_test_helper (make_reverse_comparator (lexical_cmp),
+                                 rev)
+  def test_lowercase_comparator (self):
+    self.comparator_test_helper (lowercase_cmp,
+                                 _expected_lowercase_test_data)
+
+class AbstractBtreeKeyCompareTestCase (unittest.TestCase):
+  env = None
+  db = None
+  
+  def setUp (self):
+    self.filename = self.__class__.__name__ + '.db'
+    homeDir = os.path.join (os.path.dirname (sys.argv[0]), 'db_home')
+    self.homeDir = homeDir
+    try:
+      os.mkdir (homeDir)
+    except os.error:
+      pass
+
+    env = db.DBEnv ()
+    env.open (homeDir,
+              db.DB_CREATE | db.DB_INIT_MPOOL
+              | db.DB_INIT_LOCK | db.DB_THREAD)
+    self.env = env
+
+  def tearDown (self):
+    self.closeDB ()
+    if self.env is not None:
+      self.env.close ()
+      self.env = None
+    import glob
+    map (os.remove, glob.glob (os.path.join (self.homeDir, '*')))
+
+  def addDataToDB (self, data):
+    i = 0
+    for item in data:
+      self.db.put (item, str (i))
+      i = i + 1
+
+  def createDB (self, key_comparator):
+    self.db = db.DB (self.env)
+    self.setupDB (key_comparator)
+    self.db.open (self.filename, "test", db.DB_BTREE, db.DB_CREATE)
+
+  def setupDB (self, key_comparator):
+    self.db.set_bt_compare (key_comparator)
+
+  def closeDB (self):
+    if self.db is not None:
+      self.db.close ()
+      self.db = None
+
+  def startTest (self):
+    pass
+  
+  def finishTest (self, expected = None):
+    if expected is not None:
+      self.check_results (expected)
+    self.closeDB ()
+
+  def check_results (self, expected):
+    curs = self.db.cursor ()
+    try:
+      index = 0
+      rec = curs.first ()
+      while rec:
+        key, ignore = rec
+        self.failUnless (index < len (expected),
+                         "to many values returned from cursor")
+        self.failUnless (expected[index] == key,
+                         "expected value `%s' at %d but got `%s'"
+                         % (expected[index], index, key))
+        index = index + 1
+        rec = curs.next ()
+      self.failUnless (index == len (expected),
+                       "not enough values returned from cursor")
+    finally:
+      curs.close ()
+
+class BtreeKeyCompareTestCase (AbstractBtreeKeyCompareTestCase):
+  def runCompareTest (self, comparator, data):
+    self.startTest ()
+    self.createDB (comparator)
+    self.addDataToDB (data)
+    self.finishTest (data)
+
+  def test_lexical_ordering (self):
+    self.runCompareTest (lexical_cmp, _expected_lexical_test_data)
+
+  def test_reverse_lexical_ordering (self):
+    expected_rev_data = _expected_lexical_test_data[:]
+    expected_rev_data.reverse ()
+    self.runCompareTest (make_reverse_comparator (lexical_cmp),
+                         expected_rev_data)
+
+  def test_compare_function_useless (self):
+    self.startTest ()
+    def socialist_comparator (db, l, r):
+      return 0
+    self.createDB (socialist_comparator)
+    self.addDataToDB (['b', 'a', 'd'])
+    # all things being equal the first key will be the only key
+    # in the database...  (with the last key's value fwiw)
+    self.finishTest (['b'])
+
+    
+class BtreeExceptionsTestCase (AbstractBtreeKeyCompareTestCase):
+  def test_raises_non_callable (self):
+    self.startTest ()
+    self.assertRaises (TypeError, self.createDB, 'abc')
+    self.assertRaises (TypeError, self.createDB, None)
+    self.finishTest ()
+
+  def test_set_bt_compare_with_function (self):
+    self.startTest ()
+    self.createDB (lexical_cmp)
+    self.finishTest ()
+
+  def check_results (self, results):
+    pass
+
+  def test_compare_function_incorrect (self):
+    self.startTest ()
+    def bad_comparator (db, l, r):
+      return 1
+    # verify that set_bt_compare checks that comparator(db, '', '') == 0
+    self.assertRaises (TypeError, self.createDB, bad_comparator)
+    self.finishTest ()
+
+  def test_compare_function_exception (self):
+    self.startTest ()
+    def bad_comparator (db, l, r):
+      if l == r:
+	# pass the set_bt_compare test
+	return 0
+      raise RuntimeError, "i'm a naughty comparison function"
+    self.createDB (bad_comparator)
+    print "\n*** this test should print 2 uncatchable tracebacks ***"
+    self.addDataToDB (['a', 'b', 'c'])  # this should raise, but...
+    self.finishTest ()
+
+  def test_compare_function_bad_return (self):
+    self.startTest ()
+    def bad_comparator (db, l, r):
+      if l == r:
+	# pass the set_bt_compare test
+	return 0
+      return l
+    self.createDB (bad_comparator)
+    print "\n*** this test should print 2 errors about returning an int ***"
+    self.addDataToDB (['a', 'b', 'c'])  # this should raise, but...
+    self.finishTest ()
+
+
+  def test_cannot_assign_twice (self):
+
+    def my_compare (db, a, b):
+      return 0
+    
+    self.startTest ()
+    self.createDB (my_compare)
+    try:
+      self.db.set_bt_compare (my_compare)
+      assert False, "this set should fail"
+
+    except RuntimeError, msg:
+      pass
+    
+def test_suite ():
+  res = unittest.TestSuite ()
+
+  res.addTest (unittest.makeSuite (ComparatorTests))
+  if db.version () >= (3, 3, 11):
+    res.addTest (unittest.makeSuite (BtreeExceptionsTestCase))
+    res.addTest (unittest.makeSuite (BtreeKeyCompareTestCase))
+  return res
+
+if __name__ == '__main__':
+  unittest.main (defaultTest = 'suite')