import gc
import pytest
import os

from server.storage import Storage, open_db
from lib.util import subclasses

# Find out which db engines to test
# Those that are not installed will be skipped
db_engines = []
for c in subclasses(Storage):
    try:
        c.import_module()
    except ImportError:
        db_engines.append(pytest.mark.skip(c.__name__))
    else:
        db_engines.append(c.__name__)


@pytest.fixture(params=db_engines)
def db(tmpdir, request):
    cwd = os.getcwd()
    os.chdir(str(tmpdir))
    db = open_db("db", request.param, False)
    yield db
    os.chdir(cwd)
    # Make sure all the locks and handles are closed
    del db
    gc.collect()


def test_put_get(db):
    db.put(b"x", b"y")
    assert db.get(b"x") == b"y"


def test_batch(db):
    db.put(b"a", b"1")
    with db.write_batch() as b:
        b.put(b"a", b"2")
        assert db.get(b"a") == b"1"
    assert db.get(b"a") == b"2"


def test_iterator(db):
    """
    The iterator should contain all key/value pairs starting with prefix ordered
    by key.
    """
    for i in range(5):
        db.put(b"abc" + str.encode(str(i)), str.encode(str(i)))
    db.put(b"abc", b"")
    db.put(b"a", b"xyz")
    db.put(b"abd", b"x")
    assert list(db.iterator(prefix=b"abc")) == [(b"abc", b"")] + [
            (b"abc" + str.encode(str(i)), str.encode(str(i))) for
            i in range(5)
        ]


def test_iterator_reverse(db):
    for i in range(5):
        db.put(b"abc" + str.encode(str(i)), str.encode(str(i)))
    db.put(b"a", b"xyz")
    db.put(b"abd", b"x")
    assert list(db.iterator(prefix=b"abc", reverse=True)) == [
            (b"abc" + str.encode(str(i)), str.encode(str(i))) for
            i in reversed(range(5))
        ]


def test_close(db):
    db.put(b"a", b"b")
    db.close()
    db = open_db("db", db.__class__.__name__, False)
    assert db.get(b"a") == b"b"
@@ -64,23 +64,24 @@
 torage, 
-open_db
+db_class
 %0Afrom li
@@ -517,30 +517,25 @@
    db = 
-open_db(%22db%22, 
+db_class(
 request.
@@ -539,16 +539,22 @@
 st.param
+)(%22db%22
 , False)
@@ -1798,22 +1798,17 @@
 b = 
-open_db(%22db%22, 
+db_class(
 db._
@@ -1824,16 +1824,22 @@
 __name__
+)(%22db%22
 , False)
@@ -1866,12 +1866,13 @@
 %22a%22) == b%22b%22
+%0A

Update tests