Add persistent lib to Chapter 25

25-class-metaprog/persistent/dblib_test.py

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+from textwrap import dedent
+
+import pytest
+
+from dblib import gen_columns_sql, make_schema_sql, connect, read_columns_sql
+from dblib import ColumnSchema, insert_record, fetch_record, update_record
+from dblib import NoSuchRecord, delete_record, valid_table
+
+
+@pytest.fixture
+def create_movies_sql():
+    sql = '''
+        CREATE TABLE movies (
+            pk INTEGER PRIMARY KEY,
+            title TEXT,
+            revenue REAL
+        )
+        '''
+    return dedent(sql).strip()
+
+
+@pytest.mark.parametrize(
+    'fields, expected',
+    [
+        (
+            dict(title=str, awards=int),
+            [('title', 'TEXT'), ('awards', 'INTEGER')],
+        ),
+        (
+            dict(picture=bytes, score=float),
+            [('picture', 'BLOB'), ('score', 'REAL')],
+        ),
+    ],
+)
+def test_gen_columns_sql(fields, expected):
+    result = list(gen_columns_sql(fields))
+    assert result == expected
+
+
+def test_make_schema_sql(create_movies_sql):
+    fields = dict(title=str, revenue=float)
+    result = make_schema_sql('movies', fields)
+    assert result == create_movies_sql
+
+
+def test_read_columns_sql(create_movies_sql):
+    expected = [
+        ColumnSchema(name='pk', sql_type='INTEGER'),
+        ColumnSchema(name='title', sql_type='TEXT'),
+        ColumnSchema(name='revenue', sql_type='REAL'),
+    ]
+    with connect() as con:
+        con.execute(create_movies_sql)
+        result = read_columns_sql('movies')
+    assert result == expected
+
+
+def test_read_columns_sql_no_such_table(create_movies_sql):
+    with connect() as con:
+        con.execute(create_movies_sql)
+        result = read_columns_sql('no_such_table')
+    assert result == []
+
+
+def test_insert_record(create_movies_sql):
+    fields = dict(title='Frozen', revenue=1_290_000_000)
+    with connect() as con:
+        con.execute(create_movies_sql)
+        for _ in range(3):
+            result = insert_record('movies', fields)
+    assert result == 3
+
+
+def test_fetch_record(create_movies_sql):
+    fields = dict(title='Frozen', revenue=1_290_000_000)
+    with connect() as con:
+        con.execute(create_movies_sql)
+        pk = insert_record('movies', fields)
+        row = fetch_record('movies', pk)
+    assert row == (1, 'Frozen', 1_290_000_000.0)
+
+
+def test_fetch_record_no_such_pk(create_movies_sql):
+    with connect() as con:
+        con.execute(create_movies_sql)
+        with pytest.raises(NoSuchRecord) as e:
+            fetch_record('movies', 42)
+        assert e.value.pk == 42
+
+
+def test_update_record(create_movies_sql):
+    fields = dict(title='Frozen', revenue=1_290_000_000)
+    with connect() as con:
+        con.execute(create_movies_sql)
+        pk = insert_record('movies', fields)
+        fields['revenue'] = 1_299_999_999
+        sql, values = update_record('movies', pk, fields)
+        row = fetch_record('movies', pk)
+    assert sql == 'UPDATE movies SET (title, revenue) = (?, ?) WHERE pk = ?'
+    assert values == ('Frozen', 1_299_999_999, 1)
+    assert row == (1, 'Frozen', 1_299_999_999.0)
+
+
+def test_delete_record(create_movies_sql):
+    fields = dict(title='Frozen', revenue=1_290_000_000)
+    with connect() as con:
+        con.execute(create_movies_sql)
+        pk = insert_record('movies', fields)
+        delete_record('movies', pk)
+        with pytest.raises(NoSuchRecord) as e:
+            fetch_record('movies', pk)
+        assert e.value.pk == pk
+
+
+def test_persistent_valid_table(create_movies_sql):
+    fields = dict(title=str, revenue=float)
+
+    with connect() as con:
+        con.execute(create_movies_sql)
+        con.commit()
+        assert valid_table('movies', fields)
+
+
+def test_persistent_valid_table_false(create_movies_sql):
+    # year field not in movies_sql
+    fields = dict(title=str, revenue=float, year=int)
+
+    with connect() as con:
+        con.execute(create_movies_sql)
+        con.commit()
+        assert not valid_table('movies', fields)