Tests for SQLite3 feature parity and pandas support.

Author: danielebriggi

.gitignore

@@ -14,3 +14,5 @@ main.dSYM/
 .idea
 SqliteCloud.egg-info
 src/sqlitecloud/libsqcloud.so
+
+playground.ipynb

requirements-dev.txt

@@ -14,3 +14,7 @@ isort==5.10.1
 autoflake==1.4
 pre-commit==2.17.0
 bandit==1.7.1
+# We can use the most recent compatible version because
+# this package is only used for testing compatibility
+# with pandas dataframe
+pandas>=1.1.5

src/sqlitecloud/dbapi2.py

@@ -22,6 +22,7 @@
     SQCLOUD_RESULT_TYPE,
     SQCloudConfig,
     SQCloudConnect,
+    SQCloudException,
     SqliteCloudAccount,
     SQLiteCloudDataTypes,
 )
@@ -198,12 +199,12 @@ def close(self):
 
     def commit(self):
         """
-        This method is a no-op as SQLite Cloud is currently not supporting transactions.
+        Not implementied yet.
         """
 
     def rollback(self):
         """
-        This method is a no-op as SQLite Cloud is currently not supporting transactions.
+        Not implemented yet.
         """
 
     def cursor(self):
@@ -290,15 +291,21 @@ def rowcount(self) -> int:
         """
         return self._resultset.nrows if self._is_result_rowset() else -1
 
-    def close(self) -> None:
+    @property
+    def lastrowid(self) -> Optional[int]:
+        """
+        Not implemented yet in the library.
         """
-        Closes the database connection use to create the cursor.
+        return None
 
-        Note:
-            DB-API 2.0 interface does not manage the Sqlite Cloud PubSub feature.
-            Therefore, only the main socket is closed.
+    def close(self) -> None:
+        """
+        Just mark the cursors to be no more usable in SQLite Cloud database.
+        In sqlite the `close()` is used to free up resources: https://devpress.csdn.net/python/62fe355b7e668234661931d8.html
         """
-        self._driver.disconnect(self.connection.sqlcloud_connection, True)
+        self._ensure_connection()
+
+        self._connection = None
 
     def execute(
         self,
@@ -330,6 +337,8 @@ def execute(
         Returns:
             Cursor: The cursor object.
         """
+        self._ensure_connection()
+
         prepared_statement = self._driver.prepare_statement(sql, parameters)
         result = self._driver.execute(
             prepared_statement, self.connection.sqlcloud_connection
@@ -361,6 +370,8 @@ def executemany(
         Returns:
             Cursor: The cursor object.
         """
+        self._ensure_connection()
+
         commands = ""
         for parameters in seq_of_parameters:
             prepared_statement = self._driver.prepare_statement(sql, parameters)
@@ -379,6 +390,8 @@ def fetchone(self) -> Optional[Any]:
             The next row of the query result set as a tuple,
                 or None if no more rows are available.
         """
+        self._ensure_connection()
+
         if not self._is_result_rowset():
             return None
 
@@ -395,6 +408,8 @@ def fetchmany(self, size=None) -> List[Any]:
         Returns:
             List[Tuple]: A list of rows, where each row is represented as a tuple.
         """
+        self._ensure_connection()
+
         if not self._is_result_rowset():
             return []
 
@@ -417,6 +432,8 @@ def fetchall(self) -> List[Any]:
         Returns:
             A list of rows, where each row is represented as a tuple.
         """
+        self._ensure_connection()
+
         if not self._is_result_rowset():
             return []
 
@@ -439,10 +456,22 @@ def _is_result_rowset(self) -> bool:
             self._resultset and self._resultset.tag == SQCLOUD_RESULT_TYPE.RESULT_ROWSET
         )
 
+    def _ensure_connection(self):
+        """
+        Ensure the cursor is usable or has been closed.
+
+        Raises:
+            SQCloudException: If the cursor is closed.
+        """
+        if not self._connection:
+            raise SQCloudException("The cursor is closed.")
+
     def __iter__(self) -> "Cursor":
         return self
 
     def __next__(self) -> Optional[Tuple[Any]]:
+        self._ensure_connection()
+
         if (
             not self._resultset.is_result
             and self._resultset.data
@@ -457,6 +486,3 @@ def __next__(self) -> Optional[Tuple[Any]]:
             return self._call_row_factory(out)
 
         raise StopIteration
-
-    def __len__(self) -> int:
-        return self.rowcount

src/sqlitecloud/types.py

@@ -39,7 +39,7 @@ class SQCLOUD_ROWSET(Enum):
 
 class SQCLOUD_VALUE_TYPE(Enum):
     INTEGER = "INTEGER"
-    FLOAT = "FLOAT"
+    FLOAT = "REAL"
     TEXT = "TEXT"
     BLOB = "BLOB"
     NULL = "NULL"

src/tests/assets/chinook.sqlite

@@ -0,0 +1,22 @@
+DATE,TICKER,CLOSE
+20161125,GE,31.440001
+20161123,GE,31.34
+20161122,GE,31.18
+20161121,GE,30.870001
+20161118,GE,30.67
+20161117,GE,30.790001
+20161116,GE,30.74
+20161115,GE,30.75
+20161114,GE,30.51
+20161111,GE,30.709999
+20161110,GE,30.41
+20161109,GE,29.629999
+20161108,GE,29.42
+20161107,GE,29.309999
+20161104,GE,28.440001
+20161103,GE,28.280001
+20161102,GE,28.49
+20161101,GE,28.879999
+20161031,GE,29.1
+20161028,GE,29.219999
+20161027,GE,28.629999

src/tests/assets/prices.csv

@@ -0,0 +1,67 @@
+import os
+
+import pandas as pd
+from pandas.testing import assert_frame_equal
+
+
+# Integration tests for sqlitecloud and pandas dataframe
+class TestPanads:
+    def test_insert_from_dataframe(self, sqlitecloud_dbapi2_connection):
+        conn = sqlitecloud_dbapi2_connection
+
+        dfprices = pd.read_csv(
+            os.path.join(os.path.dirname(__file__), "../assets/prices.csv")
+        )
+
+        dfmapping = pd.DataFrame(
+            {
+                "AXP": ["American Express Company"],
+                "GE": ["General Electric Company"],
+                "GS": ["Goldman Sachs Group Inc"],
+                "UTX": ["United Technologies Corporation"],
+            }
+        )
+
+        conn.executemany(
+            "DROP TABLE IF EXISTS ?", [("CLOSING_PRICES",), ("TICKER_MAPPING",)]
+        )
+
+        # arg if_exists="replace" raises the error
+        dfprices.to_sql("CLOSING_PRICES", conn, index=False)
+        dfmapping.to_sql("TICKER_MAPPING", conn, index=False)
+
+        df_actual_tables = pd.read_sql(
+            "SELECT name FROM sqlite_master WHERE type='table'", conn
+        )
+        df_actual_prices = pd.read_sql("SELECT * FROM CLOSING_PRICES", conn)
+        df_actual_mapping = pd.read_sql("SELECT * FROM TICKER_MAPPING", conn)
+
+        assert "CLOSING_PRICES" in df_actual_tables["name"].to_list()
+        assert "TICKER_MAPPING" in df_actual_tables["name"].to_list()
+        assert_frame_equal(
+            df_actual_prices,
+            dfprices,
+            check_exact=False,
+            atol=1e-6,
+            check_dtype=False,
+        )
+        assert_frame_equal(
+            df_actual_mapping,
+            dfmapping,
+            check_exact=False,
+            atol=1e-6,
+            check_dtype=False,
+        )
+
+    def test_select_into_dataframe(self, sqlitecloud_dbapi2_connection):
+        conn = sqlitecloud_dbapi2_connection
+
+        query = "SELECT * FROM albums"
+        df = pd.read_sql_query(query, conn)
+        cursor = conn.execute(query)
+
+        assert df.columns.to_list() == [
+            description[0] for description in cursor.description
+        ]
+        # compare as tuples
+        assert list(df.itertuples(index=False, name=None)) == cursor.fetchall()