Rewrite allowances using allow_iter() and allow_each() to simplify

the implementation, make behavior consistent for all allowances,
and provide a basis for user-defined allowances.  Also remove old
code and provide backwards compatible patches for api_dev1 sub-module.

Note: This commit is way too big.  It would have been better to make
a dozen smaller edits.

datatest/__init__.py

@@ -10,6 +10,9 @@
 from .sources.excel import ExcelSource
 from .sources.pandas import PandasSource
 
+from .compare import CompareSet
+from .compare import CompareDict
+
 from .error import DataError
 
 from .differences import Extra
@@ -19,8 +22,15 @@
 from .differences import NotProperSubset
 from .differences import NotProperSuperset
 
-from .compare import CompareSet
-from .compare import CompareDict
+from .allow import allow_iter
+from .allow import allow_each
+from .allow import allow_only
+from .allow import allow_any
+from .allow import allow_extra
+from .allow import allow_missing
+from .allow import allow_limit
+from .allow import allow_deviation
+from .allow import allow_percent_deviation
 
 from .runner import mandatory
 from .runner import skip
@@ -42,6 +52,7 @@
     'BaseSource',
     'SqliteSource',
     'CsvSource',
+    'AdapterSource',
     'MultiSource',
     'ExcelSource',
     'PandasSource',
@@ -60,6 +71,17 @@
     'Invalid',
     'Deviation',
 
+    # Allowance context mangers.
+    'allow_iter',
+    'allow_each',
+    'allow_only',
+    'allow_any',
+    'allow_extra',
+    'allow_missing',
+    'allow_limit',
+    'allow_deviation',
+    'allow_percent_deviation',
+
     # Test runner and command-line program.
     'mandatory',
     'skip',

datatest/__past__/api_dev1.py

@@ -3,6 +3,7 @@
 from __future__ import absolute_import
 import inspect
 import datatest
+from datatest.utils import itertools
 from datatest import DataTestCase
 
 
@@ -17,7 +18,6 @@
 DataTestCase.assertDataNotRegex = DataTestCase.assertSubjectNotRegex
 datatest.DataAssertionError = datatest.DataError
 
-
 _wrapped_find_data_source = DataTestCase._find_data_source
 @staticmethod
 def _find_data_source(name):
@@ -55,9 +55,54 @@ def _normalize_required(self, required, method, *args, **kwds):
 DataTestCase._normalize_required = _normalize_required
 
 
+# This method was removed entirely.
 def _assertDataCount(self, column, keys, required=None, msg=None, **kwds_filter):
     subject_dict = self.subject.count(column, keys, **kwds_filter)
     required = self._normalize_required(required, 'sum', column, keys, **kwds_filter)
     msg = msg or 'row counts different than {0!r} sums'.format(column)
     self.assertEqual(subject_dict, required, msg)
 DataTestCase.assertDataCount = _assertDataCount
+
+
+# Function signature and behavior was changed.
+def _allowAny(self, number=None, msg=None, **kwds_filter):
+    if number:
+        return datatest.allow_limit(number, msg, **kwds_filter)
+    return datatest.allow_any(msg, **kwds_filter)
+DataTestCase.allowAny = _allowAny
+
+
+# Function signature and behavior was changed.
+def _allowMissing(self, number=None, msg=None):
+    def function(iterable):
+        t1, t2 = itertools.tee(iterable)
+        not_allowed = []
+        count = 0
+        for x in t1:
+            if not isinstance(x, datatest.Missing):
+                not_allowed.append(x)
+            else:
+                count += 1
+            if count > number:
+                return t2  # <- EXIT! Exceeds limit, return all.
+        return not_allowed
+    return datatest.allow_iter(function, msg)
+DataTestCase.allowMissing = _allowMissing
+
+
+# Function signature and behavior was changed.
+def _allowExtra(self, number=None, msg=None):
+    def function(iterable):
+        t1, t2 = itertools.tee(iterable)
+        not_allowed = []
+        count = 0
+        for x in t1:
+            if not isinstance(x, datatest.Extra):
+                not_allowed.append(x)
+            else:
+                count += 1
+            if count > number:
+                return t2  # <- EXIT! Exceeds limit, return all.
+        return not_allowed
+    return datatest.allow_iter(function, msg)
+DataTestCase.allowExtra = _allowExtra