How to use tinydb - 10 common examples

def test_subclass():
    # Test that a new query test method in a custom subclass is properly usable
    class MyQueryClass(Query):
        def equal_double(self, rhs):
            return self._generate_test(
                lambda value: value == rhs * 2,
                ('equal_double', self._path, rhs)
            )

    query = MyQueryClass().val.equal_double('42')

    assert query({'val': '4242'})
    assert not query({'val': '42'})
    assert not query({'': None})
    assert hash(query)

def test_custom():
    def test(value):
        return value == 42

    query = Query().val.test(test)

    assert query({'val': 42})
    assert not query({'val': 40})
    assert not query({'val': '44'})
    assert not query({'': None})
    assert hash(query)

    def in_list(value, l):
        return value in l

    query = Query().val.test(in_list, tuple([25, 35]))
    assert not query({'val': 20})
    assert query({'val': 25})
    assert not query({'val': 30})
    assert query({'val': 35})
    assert not query({'val': 36})

def test_lru_cache_unlimited_explicit():
    cache = LRUCache(capacity=None)
    for i in range(100):
        cache[i] = i

    assert len(cache.lru) == 100

def test_add_new_pump(sdb, manufacturer, model):
    '''Test if adding a new unique pump works properly'''
    sdb.add_pump(manufacturer = manufacturer, model=model)
    q = Query()
    result = sdb.pumps.search((q.manufacturer == manufacturer) &
                              (q.model == model))
    expected_result = {
                        'manufacturer': manufacturer,
                        'model': model
    }
    assert result[0] == expected_result

def get(s):
        return db.get(where('name') == s)

def test_find_new_posts_and_pages():
    entries = [e for e in find_new_posts_and_pages(DB)]
    assert len(entries)
    pages = [e[1] for e in entries if str(e[0]).endswith('page.md')]
    assert len(pages)

    assert len(DB.posts.all()) == 20

    new_entries = [e for e in find_new_posts_and_pages(DB)]

    # no new posts sould be found
    assert len(DB.posts.all()) == 20
    assert len(new_entries) == 0

    [e[0].tags for e in entries]
    foo = DB.tags.search(where('name') == 'foo')
    assert foo[0]['post_ids'] == list(range(1, 16))

def test_update(db: TinyDB):
    assert len(db) == 3

    db.update({'int': 2}, where('char') == 'a')

    assert db.count(where('int') == 2) == 1
    assert db.count(where('int') == 1) == 2

def test_update_all(db: TinyDB):
    assert db.count(where('int') == 1) == 3

    db.update({'newField': True})

    assert db.count(where('newField') == True) == 3  # noqa

def test_access_storage():
    assert isinstance(TinyDB(storage=MemoryStorage).storage,
                      MemoryStorage)
    assert isinstance(TinyDB(storage=CachingMiddleware(MemoryStorage)).storage,
                      CachingMiddleware)

def test_nested():
    storage = CachingMiddleware(MemoryStorage)
    storage()  # Initialization

    # Write contents
    storage.write(doc)

    # Verify contents
    assert doc == storage.read()