gh-158277: sqlite3 CLI completer: include views in column completion

[Tony123-tech]

Fixes gh-158277.

[tanloong]

Need to remove the _col_view AS _col_view_alias, as _table does not contain the _col_view column.

[tanloong]

test_complete_view_columns() appears to have taken over the decorator intended for test_complete_functions(). Would it be better to put this test into the existing test_complete_columns()? That keeps the functionality tests together.

[Tony123-tech]

Thanks for the review! I've fixed both issues:

1. Added _col_view to the _table definition
2. Changed the decorator to the correct SQLite version (3.16.0 for pragma_table_xinfo)

[tanloong]

1. The extra _col_view_alias column check in test_complete_view_columns() provides no more infomation than _col_table_alias. Asserting _col_table_alias alone in the candidates is enough for test purpose. How about removing the _col_view_alias and _col_view definition:

CREATE TABLE _table (_col_table);
CREATE VIEW _view AS SELECT _col_table AS _col_table_alias FROM _table;

2. The @unittest.skipIf(sqlite3.sqlite_version_info < (3, 16, 0), ...) decorator, which is originally for test_complete_functions(), is occupied by the newly added test_complete_view_columns() in this PR. How about replace the test_complete_view_columns() with new tests in the already existing test_complete_columns() like this:

    def test_complete_columns(self):
        input_ = textwrap.dedent("""\
            CREATE TABLE _table (_col_table);
            CREATE TEMP TABLE _temp_table (_col_temp);
+           CREATE VIEW _view AS SELECT _col_table AS _col_table_alias FROM _table;
            ATTACH ':memory:' AS attached;
            CREATE TABLE attached._attached_table (_col_attached);

            SELECT _col_\t\tta\tFROM _table;
            .quit\n""").encode()
        output = self.write_input(input_)
        lines = output.decode().splitlines()
        indices = [
            i for i, line in enumerate(lines) if line.startswith(self.PS1)
        ]
        start, end = indices[-3], indices[-2]
        candidates = [l.strip() for l in lines[start+1:end]]

        self.assertEqual(
-           candidates, ["_col_attached", "_col_table", "_col_temp"]
+           candidates, ["_col_attached", "_col_table", "_col_table_alias", "_col_temp"]
        )