Initial Fork from https://bitbucket.org/raphaelmutschler/calibreserver/

lib/sqlalchemy/testing/util.py

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+from ..util import jython, pypy, defaultdict, decorator
+import decimal
+import gc
+import time
+import random
+import sys
+import types
+
+if jython:
+    def jython_gc_collect(*args):
+        """aggressive gc.collect for tests."""
+        gc.collect()
+        time.sleep(0.1)
+        gc.collect()
+        gc.collect()
+        return 0
+
+    # "lazy" gc, for VM's that don't GC on refcount == 0
+    gc_collect = lazy_gc = jython_gc_collect
+elif pypy:
+    def pypy_gc_collect(*args):
+        gc.collect()
+        gc.collect()
+    gc_collect = lazy_gc = pypy_gc_collect
+else:
+    # assume CPython - straight gc.collect, lazy_gc() is a pass
+    gc_collect = gc.collect
+
+    def lazy_gc():
+        pass
+
+
+def picklers():
+    picklers = set()
+    # Py2K
+    try:
+        import cPickle
+        picklers.add(cPickle)
+    except ImportError:
+        pass
+    # end Py2K
+    import pickle
+    picklers.add(pickle)
+
+    # yes, this thing needs this much testing
+    for pickle_ in picklers:
+        for protocol in -1, 0, 1, 2:
+            yield pickle_.loads, lambda d: pickle_.dumps(d, protocol)
+
+
+def round_decimal(value, prec):
+    if isinstance(value, float):
+        return round(value, prec)
+
+    # can also use shift() here but that is 2.6 only
+    return (value * decimal.Decimal("1" + "0" * prec)
+                    ).to_integral(decimal.ROUND_FLOOR) / \
+                        pow(10, prec)
+
+
+class RandomSet(set):
+    def __iter__(self):
+        l = list(set.__iter__(self))
+        random.shuffle(l)
+        return iter(l)
+
+    def pop(self):
+        index = random.randint(0, len(self) - 1)
+        item = list(set.__iter__(self))[index]
+        self.remove(item)
+        return item
+
+    def union(self, other):
+        return RandomSet(set.union(self, other))
+
+    def difference(self, other):
+        return RandomSet(set.difference(self, other))
+
+    def intersection(self, other):
+        return RandomSet(set.intersection(self, other))
+
+    def copy(self):
+        return RandomSet(self)
+
+
+def conforms_partial_ordering(tuples, sorted_elements):
+    """True if the given sorting conforms to the given partial ordering."""
+
+    deps = defaultdict(set)
+    for parent, child in tuples:
+        deps[parent].add(child)
+    for i, node in enumerate(sorted_elements):
+        for n in sorted_elements[i:]:
+            if node in deps[n]:
+                return False
+    else:
+        return True
+
+
+def all_partial_orderings(tuples, elements):
+    edges = defaultdict(set)
+    for parent, child in tuples:
+        edges[child].add(parent)
+
+    def _all_orderings(elements):
+
+        if len(elements) == 1:
+            yield list(elements)
+        else:
+            for elem in elements:
+                subset = set(elements).difference([elem])
+                if not subset.intersection(edges[elem]):
+                    for sub_ordering in _all_orderings(subset):
+                        yield [elem] + sub_ordering
+
+    return iter(_all_orderings(elements))
+
+
+def function_named(fn, name):
+    """Return a function with a given __name__.
+
+    Will assign to __name__ and return the original function if possible on
+    the Python implementation, otherwise a new function will be constructed.
+
+    This function should be phased out as much as possible
+    in favor of @decorator.   Tests that "generate" many named tests
+    should be modernized.
+
+    """
+    try:
+        fn.__name__ = name
+    except TypeError:
+        fn = types.FunctionType(fn.func_code, fn.func_globals, name,
+                          fn.func_defaults, fn.func_closure)
+    return fn
+
+
+def run_as_contextmanager(ctx, fn, *arg, **kw):
+    """Run the given function under the given contextmanager,
+    simulating the behavior of 'with' to support older
+    Python versions.
+
+    """
+
+    obj = ctx.__enter__()
+    try:
+        result = fn(obj, *arg, **kw)
+        ctx.__exit__(None, None, None)
+        return result
+    except:
+        exc_info = sys.exc_info()
+        raise_ = ctx.__exit__(*exc_info)
+        if raise_ is None:
+            raise
+        else:
+            return raise_
+
+
+def rowset(results):
+    """Converts the results of sql execution into a plain set of column tuples.
+
+    Useful for asserting the results of an unordered query.
+    """
+
+    return set([tuple(row) for row in results])
+
+
+def fail(msg):
+    assert False, msg
+
+
+@decorator
+def provide_metadata(fn, *args, **kw):
+    """Provide bound MetaData for a single test, dropping afterwards."""
+
+    from . import config
+    from sqlalchemy import schema
+
+    metadata = schema.MetaData(config.db)
+    self = args[0]
+    prev_meta = getattr(self, 'metadata', None)
+    self.metadata = metadata
+    try:
+        return fn(*args, **kw)
+    finally:
+        metadata.drop_all()
+        self.metadata = prev_meta
+
+
+class adict(dict):
+    """Dict keys available as attributes.  Shadows."""
+    def __getattribute__(self, key):
+        try:
+            return self[key]
+        except KeyError:
+            return dict.__getattribute__(self, key)
+
+    def get_all(self, *keys):
+        return tuple([self[key] for key in keys])