File: test_dataset.py

package info (click to toggle)
python-dataset 1.6.2-3
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 456 kB
  • sloc: python: 1,420; makefile: 162
file content (603 lines) | stat: -rw-r--r-- 21,987 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
import os
import unittest
from datetime import datetime
from collections import OrderedDict
from sqlalchemy import TEXT, BIGINT
from sqlalchemy.exc import IntegrityError, SQLAlchemyError, ArgumentError

from dataset import connect, chunked

from .sample_data import TEST_DATA, TEST_CITY_1


class DatabaseTestCase(unittest.TestCase):
    def setUp(self):
        self.db = connect()
        self.tbl = self.db["weather"]
        assert not self.db.has_table("weather")
        self.tbl.insert_many(TEST_DATA)
        # table is only created after insert statement
        assert self.db.has_table("weather")

    def tearDown(self):
        for table in self.db.tables:
            self.db[table].drop()

    def test_valid_database_url(self):
        assert self.db.url, os.environ["DATABASE_URL"]

    def test_database_url_query_string(self):
        db = connect("sqlite:///:memory:/?cached_statements=1")
        assert "cached_statements" in db.url, db.url

    def test_tables(self):
        assert self.db.tables == ["weather"], self.db.tables

    def test_contains(self):
        assert "weather" in self.db, self.db.tables

    def test_create_table(self):
        table = self.db["foo"]
        assert self.db.has_table(table.table.name)
        assert len(table.table.columns) == 1, table.table.columns
        assert "id" in table.table.c, table.table.c

    def test_create_table_no_ids(self):
        if "mysql" in self.db.engine.dialect.dbapi.__name__:
            return
        if "sqlite" in self.db.engine.dialect.dbapi.__name__:
            return
        table = self.db.create_table("foo_no_id", primary_id=False)
        assert table.table.exists()
        assert len(table.table.columns) == 0, table.table.columns

    def test_create_table_custom_id1(self):
        pid = "string_id"
        table = self.db.create_table("foo2", pid, self.db.types.string(255))
        assert self.db.has_table(table.table.name)
        assert len(table.table.columns) == 1, table.table.columns
        assert pid in table.table.c, table.table.c
        table.insert({pid: "foobar"})
        assert table.find_one(string_id="foobar")[pid] == "foobar"

    def test_create_table_custom_id2(self):
        pid = "string_id"
        table = self.db.create_table("foo3", pid, self.db.types.string(50))
        assert self.db.has_table(table.table.name)
        assert len(table.table.columns) == 1, table.table.columns
        assert pid in table.table.c, table.table.c

        table.insert({pid: "foobar"})
        assert table.find_one(string_id="foobar")[pid] == "foobar"

    def test_create_table_custom_id3(self):
        pid = "int_id"
        table = self.db.create_table("foo4", primary_id=pid)
        assert self.db.has_table(table.table.name)
        assert len(table.table.columns) == 1, table.table.columns
        assert pid in table.table.c, table.table.c

        table.insert({pid: 123})
        table.insert({pid: 124})
        assert table.find_one(int_id=123)[pid] == 123
        assert table.find_one(int_id=124)[pid] == 124
        self.assertRaises(IntegrityError, lambda: table.insert({pid: 123}))

    def test_create_table_shorthand1(self):
        pid = "int_id"
        table = self.db.get_table("foo5", pid)
        assert len(table.table.columns) == 1, table.table.columns
        assert pid in table.table.c, table.table.c

        table.insert({"int_id": 123})
        table.insert({"int_id": 124})
        assert table.find_one(int_id=123)["int_id"] == 123
        assert table.find_one(int_id=124)["int_id"] == 124
        self.assertRaises(IntegrityError, lambda: table.insert({"int_id": 123}))

    def test_create_table_shorthand2(self):
        pid = "string_id"
        table = self.db.get_table(
            "foo6", primary_id=pid, primary_type=self.db.types.string(255)
        )
        assert len(table.table.columns) == 1, table.table.columns
        assert pid in table.table.c, table.table.c

        table.insert({"string_id": "foobar"})
        assert table.find_one(string_id="foobar")["string_id"] == "foobar"

    def test_with(self):
        init_length = len(self.db["weather"])
        with self.assertRaises(ValueError):
            with self.db as tx:
                tx["weather"].insert(
                    {
                        "date": datetime(2011, 1, 1),
                        "temperature": 1,
                        "place": "tmp_place",
                    }
                )
                raise ValueError()
        assert len(self.db["weather"]) == init_length

    def test_invalid_values(self):
        if "mysql" in self.db.engine.dialect.dbapi.__name__:
            # WARNING: mysql seems to be doing some weird type casting
            # upon insert. The mysql-python driver is not affected but
            # it isn't compatible with Python 3
            # Conclusion: use postgresql.
            return
        with self.assertRaises(SQLAlchemyError):
            tbl = self.db["weather"]
            tbl.insert(
                {"date": True, "temperature": "wrong_value", "place": "tmp_place"}
            )

    def test_load_table(self):
        tbl = self.db.load_table("weather")
        assert tbl.table.name == self.tbl.table.name

    def test_query(self):
        r = self.db.query("SELECT COUNT(*) AS num FROM weather").next()
        assert r["num"] == len(TEST_DATA), r

    def test_table_cache_updates(self):
        tbl1 = self.db.get_table("people")
        data = OrderedDict([("first_name", "John"), ("last_name", "Smith")])
        tbl1.insert(data)
        data["id"] = 1
        tbl2 = self.db.get_table("people")
        assert dict(tbl2.all().next()) == dict(data), (tbl2.all().next(), data)


class TableTestCase(unittest.TestCase):
    def setUp(self):
        self.db = connect()
        self.tbl = self.db["weather"]
        for row in TEST_DATA:
            self.tbl.insert(row)

    def tearDown(self):
        self.tbl.drop()

    def test_insert(self):
        assert len(self.tbl) == len(TEST_DATA), len(self.tbl)
        last_id = self.tbl.insert(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"}
        )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)
        assert self.tbl.find_one(id=last_id)["place"] == "Berlin"

    def test_insert_ignore(self):
        self.tbl.insert_ignore(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"},
            ["place"],
        )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)
        self.tbl.insert_ignore(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"},
            ["place"],
        )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)

    def test_insert_ignore_all_key(self):
        for i in range(0, 4):
            self.tbl.insert_ignore(
                {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"},
                ["date", "temperature", "place"],
            )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)

    def test_insert_json(self):
        last_id = self.tbl.insert(
            {
                "date": datetime(2011, 1, 2),
                "temperature": -10,
                "place": "Berlin",
                "info": {
                    "currency": "EUR",
                    "language": "German",
                    "population": 3292365,
                },
            }
        )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)
        assert self.tbl.find_one(id=last_id)["place"] == "Berlin"

    def test_upsert(self):
        self.tbl.upsert(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"},
            ["place"],
        )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)
        self.tbl.upsert(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"},
            ["place"],
        )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)

    def test_upsert_single_column(self):
        table = self.db["banana_single_col"]
        table.upsert({"color": "Yellow"}, ["color"])
        assert len(table) == 1, len(table)
        table.upsert({"color": "Yellow"}, ["color"])
        assert len(table) == 1, len(table)

    def test_upsert_all_key(self):
        assert len(self.tbl) == len(TEST_DATA), len(self.tbl)
        for i in range(0, 2):
            self.tbl.upsert(
                {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"},
                ["date", "temperature", "place"],
            )
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)

    def test_upsert_id(self):
        table = self.db["banana_with_id"]
        data = dict(id=10, title="I am a banana!")
        table.upsert(data, ["id"])
        assert len(table) == 1, len(table)

    def test_update_while_iter(self):
        for row in self.tbl:
            row["foo"] = "bar"
            self.tbl.update(row, ["place", "date"])
        assert len(self.tbl) == len(TEST_DATA), len(self.tbl)

    def test_weird_column_names(self):
        with self.assertRaises(ValueError):
            self.tbl.insert(
                {
                    "date": datetime(2011, 1, 2),
                    "temperature": -10,
                    "foo.bar": "Berlin",
                    "qux.bar": "Huhu",
                }
            )

    def test_cased_column_names(self):
        tbl = self.db["cased_column_names"]
        tbl.insert({"place": "Berlin"})
        tbl.insert({"Place": "Berlin"})
        tbl.insert({"PLACE ": "Berlin"})
        assert len(tbl.columns) == 2, tbl.columns
        assert len(list(tbl.find(Place="Berlin"))) == 3
        assert len(list(tbl.find(place="Berlin"))) == 3
        assert len(list(tbl.find(PLACE="Berlin"))) == 3

    def test_invalid_column_names(self):
        tbl = self.db["weather"]
        with self.assertRaises(ValueError):
            tbl.insert({None: "banana"})

        with self.assertRaises(ValueError):
            tbl.insert({"": "banana"})

        with self.assertRaises(ValueError):
            tbl.insert({"-": "banana"})

    def test_delete(self):
        self.tbl.insert(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"}
        )
        original_count = len(self.tbl)
        assert len(self.tbl) == len(TEST_DATA) + 1, len(self.tbl)
        # Test bad use of API
        with self.assertRaises(ArgumentError):
            self.tbl.delete({"place": "Berlin"})
        assert len(self.tbl) == original_count, len(self.tbl)

        assert self.tbl.delete(place="Berlin") is True, "should return 1"
        assert len(self.tbl) == len(TEST_DATA), len(self.tbl)
        assert self.tbl.delete() is True, "should return non zero"
        assert len(self.tbl) == 0, len(self.tbl)

    def test_repr(self):
        assert (
            repr(self.tbl) == "<Table(weather)>"
        ), "the representation should be <Table(weather)>"

    def test_delete_nonexist_entry(self):
        assert (
            self.tbl.delete(place="Berlin") is False
        ), "entry not exist, should fail to delete"

    def test_find_one(self):
        self.tbl.insert(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"}
        )
        d = self.tbl.find_one(place="Berlin")
        assert d["temperature"] == -10, d
        d = self.tbl.find_one(place="Atlantis")
        assert d is None, d

    def test_count(self):
        assert len(self.tbl) == 6, len(self.tbl)
        length = self.tbl.count(place=TEST_CITY_1)
        assert length == 3, length

    def test_find(self):
        ds = list(self.tbl.find(place=TEST_CITY_1))
        assert len(ds) == 3, ds
        ds = list(self.tbl.find(place=TEST_CITY_1, _limit=2))
        assert len(ds) == 2, ds
        ds = list(self.tbl.find(place=TEST_CITY_1, _limit=2, _step=1))
        assert len(ds) == 2, ds
        ds = list(self.tbl.find(place=TEST_CITY_1, _limit=1, _step=2))
        assert len(ds) == 1, ds
        ds = list(self.tbl.find(_step=2))
        assert len(ds) == len(TEST_DATA), ds
        ds = list(self.tbl.find(order_by=["temperature"]))
        assert ds[0]["temperature"] == -1, ds
        ds = list(self.tbl.find(order_by=["-temperature"]))
        assert ds[0]["temperature"] == 8, ds
        ds = list(self.tbl.find(self.tbl.table.columns.temperature > 4))
        assert len(ds) == 3, ds

    def test_find_dsl(self):
        ds = list(self.tbl.find(place={"like": "%lw%"}))
        assert len(ds) == 3, ds
        ds = list(self.tbl.find(temperature={">": 5}))
        assert len(ds) == 2, ds
        ds = list(self.tbl.find(temperature={">=": 5}))
        assert len(ds) == 3, ds
        ds = list(self.tbl.find(temperature={"<": 0}))
        assert len(ds) == 1, ds
        ds = list(self.tbl.find(temperature={"<=": 0}))
        assert len(ds) == 2, ds
        ds = list(self.tbl.find(temperature={"!=": -1}))
        assert len(ds) == 5, ds
        ds = list(self.tbl.find(temperature={"between": [5, 8]}))
        assert len(ds) == 3, ds
        ds = list(self.tbl.find(place={"=": "G€lway"}))
        assert len(ds) == 3, ds
        ds = list(self.tbl.find(place={"ilike": "%LwAy"}))
        assert len(ds) == 3, ds

    def test_offset(self):
        ds = list(self.tbl.find(place=TEST_CITY_1, _offset=1))
        assert len(ds) == 2, ds
        ds = list(self.tbl.find(place=TEST_CITY_1, _limit=2, _offset=2))
        assert len(ds) == 1, ds

    def test_streamed(self):
        ds = list(self.tbl.find(place=TEST_CITY_1, _streamed=True, _step=1))
        assert len(ds) == 3, len(ds)
        for row in self.tbl.find(place=TEST_CITY_1, _streamed=True, _step=1):
            row["temperature"] = -1
            self.tbl.update(row, ["id"])

    def test_distinct(self):
        x = list(self.tbl.distinct("place"))
        assert len(x) == 2, x
        x = list(self.tbl.distinct("place", "date"))
        assert len(x) == 6, x
        x = list(
            self.tbl.distinct(
                "place",
                "date",
                self.tbl.table.columns.date >= datetime(2011, 1, 2, 0, 0),
            )
        )
        assert len(x) == 4, x

        x = list(self.tbl.distinct("temperature", place="B€rkeley"))
        assert len(x) == 3, x
        x = list(self.tbl.distinct("temperature", place=["B€rkeley", "G€lway"]))
        assert len(x) == 6, x

    def test_insert_many(self):
        data = TEST_DATA * 100
        self.tbl.insert_many(data, chunk_size=13)
        assert len(self.tbl) == len(data) + 6, (len(self.tbl), len(data))

    def test_chunked_insert(self):
        data = TEST_DATA * 100
        with chunked.ChunkedInsert(self.tbl) as chunk_tbl:
            for item in data:
                chunk_tbl.insert(item)
        assert len(self.tbl) == len(data) + 6, (len(self.tbl), len(data))

    def test_chunked_insert_callback(self):
        data = TEST_DATA * 100
        N = 0

        def callback(queue):
            nonlocal N
            N += len(queue)

        with chunked.ChunkedInsert(self.tbl, callback=callback) as chunk_tbl:
            for item in data:
                chunk_tbl.insert(item)
        assert len(data) == N
        assert len(self.tbl) == len(data) + 6

    def test_update_many(self):
        tbl = self.db["update_many_test"]
        tbl.insert_many([dict(temp=10), dict(temp=20), dict(temp=30)])
        tbl.update_many([dict(id=1, temp=50), dict(id=3, temp=50)], "id")

        # Ensure data has been updated.
        assert tbl.find_one(id=1)["temp"] == tbl.find_one(id=3)["temp"]

    def test_chunked_update(self):
        tbl = self.db["update_many_test"]
        tbl.insert_many(
            [
                dict(temp=10, location="asdf"),
                dict(temp=20, location="qwer"),
                dict(temp=30, location="asdf"),
            ]
        )

        chunked_tbl = chunked.ChunkedUpdate(tbl, "id")
        chunked_tbl.update(dict(id=1, temp=50))
        chunked_tbl.update(dict(id=2, location="asdf"))
        chunked_tbl.update(dict(id=3, temp=50))
        chunked_tbl.flush()

        # Ensure data has been updated.
        assert tbl.find_one(id=1)["temp"] == tbl.find_one(id=3)["temp"] == 50
        assert (
            tbl.find_one(id=2)["location"] == tbl.find_one(id=3)["location"] == "asdf"
        )  # noqa

    def test_upsert_many(self):
        # Also tests updating on records with different attributes
        tbl = self.db["upsert_many_test"]

        W = 100
        tbl.upsert_many([dict(age=10), dict(weight=W)], "id")
        assert tbl.find_one(id=1)["age"] == 10

        tbl.upsert_many([dict(id=1, age=70), dict(id=2, weight=W / 2)], "id")
        assert tbl.find_one(id=2)["weight"] == W / 2

    def test_drop_operations(self):
        assert self.tbl._table is not None, "table shouldn't be dropped yet"
        self.tbl.drop()
        assert self.tbl._table is None, "table should be dropped now"
        assert list(self.tbl.all()) == [], self.tbl.all()
        assert self.tbl.count() == 0, self.tbl.count()

    def test_table_drop(self):
        assert "weather" in self.db
        self.db["weather"].drop()
        assert "weather" not in self.db

    def test_table_drop_then_create(self):
        assert "weather" in self.db
        self.db["weather"].drop()
        assert "weather" not in self.db
        self.db["weather"].insert({"foo": "bar"})

    def test_columns(self):
        cols = self.tbl.columns
        assert len(list(cols)) == 4, "column count mismatch"
        assert "date" in cols and "temperature" in cols and "place" in cols

    def test_drop_column(self):
        try:
            self.tbl.drop_column("date")
            assert "date" not in self.tbl.columns
        except RuntimeError:
            pass

    def test_iter(self):
        c = 0
        for row in self.tbl:
            c += 1
        assert c == len(self.tbl)

    def test_update(self):
        date = datetime(2011, 1, 2)
        res = self.tbl.update(
            {"date": date, "temperature": -10, "place": TEST_CITY_1}, ["place", "date"]
        )
        assert res, "update should return True"
        m = self.tbl.find_one(place=TEST_CITY_1, date=date)
        assert m["temperature"] == -10, (
            "new temp. should be -10 but is %d" % m["temperature"]
        )

    def test_create_column(self):
        tbl = self.tbl
        flt = self.db.types.float
        tbl.create_column("foo", flt)
        assert "foo" in tbl.table.c, tbl.table.c
        assert isinstance(tbl.table.c["foo"].type, flt), tbl.table.c["foo"].type
        assert "foo" in tbl.columns, tbl.columns

    def test_ensure_column(self):
        tbl = self.tbl
        flt = self.db.types.float
        tbl.create_column_by_example("foo", 0.1)
        assert "foo" in tbl.table.c, tbl.table.c
        assert isinstance(tbl.table.c["foo"].type, flt), tbl.table.c["bar"].type
        tbl.create_column_by_example("bar", 1)
        assert "bar" in tbl.table.c, tbl.table.c
        assert isinstance(tbl.table.c["bar"].type, BIGINT), tbl.table.c["bar"].type
        tbl.create_column_by_example("pippo", "test")
        assert "pippo" in tbl.table.c, tbl.table.c
        assert isinstance(tbl.table.c["pippo"].type, TEXT), tbl.table.c["pippo"].type
        tbl.create_column_by_example("bigbar", 11111111111)
        assert "bigbar" in tbl.table.c, tbl.table.c
        assert isinstance(tbl.table.c["bigbar"].type, BIGINT), tbl.table.c[
            "bigbar"
        ].type
        tbl.create_column_by_example("littlebar", -11111111111)
        assert "littlebar" in tbl.table.c, tbl.table.c
        assert isinstance(tbl.table.c["littlebar"].type, BIGINT), tbl.table.c[
            "littlebar"
        ].type

    def test_key_order(self):
        res = self.db.query("SELECT temperature, place FROM weather LIMIT 1")
        keys = list(res.next().keys())
        assert keys[0] == "temperature"
        assert keys[1] == "place"

    def test_empty_query(self):
        empty = list(self.tbl.find(place="not in data"))
        assert len(empty) == 0, empty


class Constructor(dict):
    """Very simple low-functionality extension to ``dict`` to
    provide attribute access to dictionary contents"""

    def __getattr__(self, name):
        return self[name]


class RowTypeTestCase(unittest.TestCase):
    def setUp(self):
        self.db = connect(row_type=Constructor)
        self.tbl = self.db["weather"]
        for row in TEST_DATA:
            self.tbl.insert(row)

    def tearDown(self):
        for table in self.db.tables:
            self.db[table].drop()

    def test_find_one(self):
        self.tbl.insert(
            {"date": datetime(2011, 1, 2), "temperature": -10, "place": "Berlin"}
        )
        d = self.tbl.find_one(place="Berlin")
        assert d["temperature"] == -10, d
        assert d.temperature == -10, d
        d = self.tbl.find_one(place="Atlantis")
        assert d is None, d

    def test_find(self):
        ds = list(self.tbl.find(place=TEST_CITY_1))
        assert len(ds) == 3, ds
        for item in ds:
            assert isinstance(item, Constructor), item
        ds = list(self.tbl.find(place=TEST_CITY_1, _limit=2))
        assert len(ds) == 2, ds
        for item in ds:
            assert isinstance(item, Constructor), item

    def test_distinct(self):
        x = list(self.tbl.distinct("place"))
        assert len(x) == 2, x
        for item in x:
            assert isinstance(item, Constructor), item
        x = list(self.tbl.distinct("place", "date"))
        assert len(x) == 6, x
        for item in x:
            assert isinstance(item, Constructor), item

    def test_iter(self):
        c = 0
        for row in self.tbl:
            c += 1
            assert isinstance(row, Constructor), row
        assert c == len(self.tbl)


if __name__ == "__main__":
    unittest.main()