trying different approaches to test layout. in this one, the testing modules

become an externally usable package but still remains within the main sqlalchemy parent package.
in this system, we use kind of an ugly hack to get the noseplugin imported outside of the
"sqlalchemy" package, while still making it available within sqlalchemy for usage by
third party libraries.

1 files changed, 196 insertions, 0 deletions

diff --git a/lib/sqlalchemy/testing/util.py b/lib/sqlalchemy/testing/util.py
new file mode 100644
index 000000000..625b9e6a5
--- /dev/null
+++ b/lib/sqlalchemy/testing/util.py
@@ -0,0 +1,196 @@
+from sqlalchemy.util import jython, pypy, defaultdict, decorator
+from sqlalchemy.util.compat 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
+    lazy_gc = jython_gc_collect
+elif pypy:
+    def pypy_gc_collect(*args):
+        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])
+
+