Adding two basic test cases for dividing the work of implementing parse and format functions

tests/test_query_parser.py

@@ -10,6 +10,131 @@
 
 parser = QueryParser()
 
+
+def test_basic_parse():
+
+    # Construct input query text
+    sql = """
+        SELECT e.name, d.name as dept_name, COUNT(*) as emp_count
+        FROM employees e JOIN departments d ON e.department_id = d.id
+        WHERE e.salary > 40000 AND e.age < 60
+        GROUP BY d.id, d.name
+        HAVING COUNT(*) > 2
+        ORDER BY dept_name, emp_count DESC
+        LIMIT 10 OFFSET 5
+    """
+
+    # Construct expected AST
+    # Tables
+    emp_table = TableNode("employees", "e")
+    dept_table = TableNode("departments", "d")
+    # Columns
+    emp_name = ColumnNode("name", _parent_alias="e")
+    dept_name = ColumnNode("name", "dept_name", "d")
+    emp_salary = ColumnNode("salary", _parent_alias="e")
+    emp_age = ColumnNode("age", _parent_alias="e")
+    emp_dept_id = ColumnNode("department_id", _parent_alias="e")
+    dept_id = ColumnNode("id", _parent_alias="d")
+    count_star = FunctionNode("COUNT", {ColumnNode("*")})
+    count_alias = ColumnNode("emp_count")  # This would be the alias for COUNT(*)
+    # SELECT clause
+    select_clause = SelectNode({emp_name, dept_name, count_star})
+    # FROM clause (with implicit JOIN logic)
+    from_clause = FromNode({emp_table, dept_table})
+    # WHERE clause
+    salary_condition = OperatorNode(emp_salary, ">", LiteralNode(40000))
+    age_condition = OperatorNode(emp_age, "<", LiteralNode(60))
+    where_condition = OperatorNode(salary_condition, "AND", age_condition)
+    where_clause = WhereNode({where_condition})
+    # GROUP BY clause
+    group_by_clause = GroupByNode({dept_id, dept_name})
+    # HAVING clause
+    having_condition = OperatorNode(count_star, ">", LiteralNode(2))
+    having_clause = HavingNode({having_condition})
+    # ORDER BY clause
+    order_by_clause = OrderByNode({dept_name, count_alias})
+    # LIMIT and OFFSET
+    limit_clause = LimitNode(10)
+    offset_clause = OffsetNode(5)
+    # Complete query
+    expected_ast = QueryNode(
+        _select=select_clause,
+        _from=from_clause,
+        _where=where_clause,
+        _group_by=group_by_clause,
+        _having=having_clause,
+        _order_by=order_by_clause,
+        _limit=limit_clause,
+        _offset=offset_clause
+    )
+
+    ast = parser.parse(sql)
+
+    assert ast == expected_ast
+
+
+def test_basic_format():
+
+    # Construct input AST
+    # Tables
+    emp_table = TableNode("employees", "e")
+    dept_table = TableNode("departments", "d")
+    # Columns
+    emp_name = ColumnNode("name", _parent_alias="e")
+    dept_name = ColumnNode("name", "dept_name", "d")
+    emp_salary = ColumnNode("salary", _parent_alias="e")
+    emp_age = ColumnNode("age", _parent_alias="e")
+    emp_dept_id = ColumnNode("department_id", _parent_alias="e")
+    dept_id = ColumnNode("id", _parent_alias="d")
+    count_star = FunctionNode("COUNT", {ColumnNode("*")})
+    count_alias = ColumnNode("emp_count")  # This would be the alias for COUNT(*)
+    # SELECT clause
+    select_clause = SelectNode({emp_name, dept_name, count_star})
+    # FROM clause (with implicit JOIN logic)
+    from_clause = FromNode({emp_table, dept_table})
+    # WHERE clause
+    salary_condition = OperatorNode(emp_salary, ">", LiteralNode(40000))
+    age_condition = OperatorNode(emp_age, "<", LiteralNode(60))
+    where_condition = OperatorNode(salary_condition, "AND", age_condition)
+    where_clause = WhereNode({where_condition})
+    # GROUP BY clause
+    group_by_clause = GroupByNode({dept_id, dept_name})
+    # HAVING clause
+    having_condition = OperatorNode(count_star, ">", LiteralNode(2))
+    having_clause = HavingNode({having_condition})
+    # ORDER BY clause
+    order_by_clause = OrderByNode({dept_name, count_alias})
+    # LIMIT and OFFSET
+    limit_clause = LimitNode(10)
+    offset_clause = OffsetNode(5)
+    # Complete query
+    ast = QueryNode(
+        _select=select_clause,
+        _from=from_clause,
+        _where=where_clause,
+        _group_by=group_by_clause,
+        _having=having_clause,
+        _order_by=order_by_clause,
+        _limit=limit_clause,
+        _offset=offset_clause
+    )
+
+    # Construct expected query text
+    expected_sql = """
+        SELECT e.name, d.name as dept_name, COUNT(*) as emp_count
+        FROM employees e JOIN departments d ON e.department_id = d.id
+        WHERE e.salary > 40000 AND e.age < 60
+        GROUP BY d.id, d.name
+        HAVING COUNT(*) > 2
+        ORDER BY dept_name, emp_count DESC
+        LIMIT 10 OFFSET 5
+    """
+
+    sql = parser.format(ast)
+
+    assert sql == expected_sql
+
+
 def test_parse_1():
     query = get_query(1)
     sql = query['pattern']