Added basic tests for settings.DATABASES populating

django.db.connections with lazy db connections. 


git-svn-id: http://code.djangoproject.com/svn/django/branches/multiple-db-support@3231 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/othertests/multiple_databases.py

@@ -0,0 +1,116 @@
+import copy
+import os
+import sys
+import tempfile
+from django.conf import settings
+from django import db
+from runtests import doctest, DjangoDoctestRunner, error_list
+
+# database files
+fh, db_a = tempfile.mkstemp()
+os.close(fh)
+fh, db_b = tempfile.mkstemp()
+os.close(fh)
+
+# patches
+tmp_settings = None
+tmp_connections = None
+
+# tests
+test = r"""
+XXX. Using multiple database connections
+
+Django normally uses only a single database connection. However, support is
+available for connecting to any number of different, named databases.
+
+Named connections are defined in your settings module. Create a
+`DATABASES` variable that is a dict, mapping connection names to their
+particulars. The particulars are defined in a dict with the same keys
+as the variable names as are used to define the default connection.
+
+.. note::
+
+    Please note that this uses the sqlite3 backend and writes temporary
+    database files to disk. This test will fail unless sqlite3 is
+    installed and your temp directory is writable.
+
+    >>> from django.conf import settings
+    >>> settings.DATABASES = { 
+    ...     'a': { 'DATABASE_ENGINE': 'sqlite3',
+    ...            'DATABASE_NAME': db_a
+    ...     },
+    ...     'b': { 'DATABASE_ENGINE': 'sqlite3',
+    ...            'DATABASE_NAME': db_b
+    ...     }}
+
+Connections are established lazily, when requested by name. When
+accessed, `connections[database]` holds a `ConnectionInfo` instance,
+with the attributes: `DatabaseError`, `backend`,
+`get_introspection_module`, `get_creation_module`, and
+`runshell`. Access connections through the `connections` property of
+the `django.db` module:
+
+    >>> from django.db import connections
+    >>> connections['a'].settings.DATABASE_NAME == db_a
+    True
+    >>> connections['b'].settings.DATABASE_NAME == db_b
+    True
+    
+Invalid connection names raise ImproperlyConfigured:
+
+    >>> connections['bad']
+    Traceback (most recent call last):
+        ...
+    ImproperlyConfigured: No database connection 'bad' has been configured
+"""
+
+def cleanup():
+    if os.path.exists(db_a):
+        os.unlink(db_a)
+    if os.path.exists(db_b):
+        os.unlink(db_b)        
+
+def setup():
+    global tmp_settings, tmp_connections
+    try:
+        tmp_connections = db.connections
+        db.connections = db.LazyConnectionManager()
+        tmp_settings = copy.copy(settings.DATABASES)
+    except AttributeError:
+        pass
+    
+def teardown():
+    try:
+        db.connections = tmp_connections
+        settings.DATABASES = tmp_settings
+    except AttributeError:
+        pass
+    cleanup()
+
+def run_tests(verbosity_level):
+    setup()
+    try:
+        main(verbosity_level)
+    finally:
+        teardown()
+
+def main(verbosity_level):
+    mod = sys.modules[__name__]
+    p = doctest.DocTestParser()
+    dtest = p.get_doctest(mod.test, mod.__dict__, __name__, None, None)
+    runner = DjangoDoctestRunner(verbosity_level=verbosity_level,
+                                 verbose=False)
+    runner.run(dtest, clear_globs=True, out=sys.stdout.write)
+    if error_list:
+        out = []
+        for d in error_list:
+            out.extend([d['title'], "=" * len(d['title']),
+                        d['description']])
+
+        raise Exception, "%s multiple_databases test%s failed:\n\n %s" \
+              % (len(error_list),
+                  len(error_list) != 1 and 's' or '',
+                 '\n'.join(out))
+            
+if __name__ == '__main__':
+    run_tests(1)