test: add 17 tests, fix double-sort bug, update docs and CI

.github/workflows/ci.yml

@@ -74,7 +74,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.11", "3.12", "3.13"]
+        python-version: ["3.11", "3.12", "3.13", "3.14"]
     steps:
       - name: Harden runner
         uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4

.gitignore

@@ -11,6 +11,7 @@ build/
 coverage.xml
 htmlcov/
 .pytest_cache/
+.mypy_cache/
 
 # IDE
 .vscode/

CONTRIBUTING.md

@@ -0,0 +1,70 @@
+# Contributing to MiniDB
+
+## Prerequisites
+
+- Python 3.11 or later
+- No external dependencies for the library itself
+
+## Development Setup
+
+```bash
+git clone https://github.com/SebTardif/MiniDB.git
+cd MiniDB
+
+# Install dev tools
+pip install ruff mypy pytest pytest-cov
+
+# Verify everything works
+python -m pytest tests/ -v
+python main.py
+```
+
+## Pre-Commit Checks
+
+Run these before submitting a PR (CI enforces all of them):
+
+```bash
+# Lint
+ruff check .
+
+# Format
+ruff format --check .
+
+# Type check
+mypy minidb/
+
+# Tests
+python -m pytest tests/ -v
+```
+
+## Commit Message Convention
+
+This project uses [Conventional Commits](https://www.conventionalcommits.org/)
+for automatic versioning via semantic-release.
+
+Allowed prefixes: `feat`, `fix`, `docs`, `style`, `refactor`, `perf`,
+`test`, `build`, `ci`, `chore`, `revert`.
+
+Examples:
+- `feat: add DISTINCT keyword support`
+- `fix: handle NULL in ORDER BY correctly`
+- `test: add edge case tests for JOIN`
+- `docs: update SQL syntax reference`
+
+## Project Structure
+
+```
+minidb/
+  database.py      # MiniDB main class (facade)
+  parser.py        # SQL lexer and parser
+  query.py         # Query execution engine
+  table.py         # Table storage and row management
+  column.py        # Column and Schema definitions
+  index.py         # Hash-based indexing
+  planner.py       # Query planner (index vs table scan)
+  persistence.py   # JSON serialization
+  types.py         # Type definitions and enums
+  errors.py        # Custom exception hierarchy
+tests/
+  test_*.py        # Test files matching source modules
+```

README.md

@@ -12,7 +12,7 @@ A miniature in-memory database with SQL-like query support, built from scratch u
   - GROUP BY with aggregations
   - LIMIT clause
 - **Aggregations**: COUNT, SUM, AVG, MIN, MAX
-- **JOINs**: INNER JOIN between tables
+- **JOINs**: INNER JOIN and LEFT JOIN between tables
 - **Indexing**: Automatic hash-based indexing on primary keys
 - **Query Planner**: Chooses between index scans and table scans
 - **Persistence**: Save/load database to JSON files with versioning
@@ -23,7 +23,7 @@ No installation required! MiniDB uses only Python standard library.
 
 ```bash
 # Just clone and use
-git clone <repo-url>
+git clone https://github.com/SebTardif/MiniDB.git
 cd MiniDB
 python -m pytest tests/ -v  # Run tests
 python main.py              # Run demo
@@ -161,6 +161,11 @@ LIMIT 10
 SELECT t1.col, t2.col
 FROM t1
 JOIN t2 ON t1.id = t2.t1_id
+
+-- LEFT JOIN (includes unmatched left rows with NULLs)
+SELECT t1.col, t2.col
+FROM t1
+LEFT JOIN t2 ON t1.id = t2.t1_id
 ```
 
 ### UPDATE
@@ -194,7 +199,7 @@ minidb/
 
 ## Test Suite
 
-MiniDB includes a comprehensive test suite with 29+ test cases:
+MiniDB includes a comprehensive test suite with 95+ test cases:
 
 ```bash
 # Run all tests
@@ -211,7 +216,7 @@ python -m pytest tests/ -v --cov=minidb
 
 - **test_database.py**: Database lifecycle and table management
 - **test_crud.py**: INSERT, SELECT, UPDATE, DELETE operations
-- **test_queries.py**: WHERE, ORDER BY, LIMIT
+- **test_queries.py**: WHERE, ORDER BY, LIMIT, parser errors, type validation
 - **test_aggregations.py**: COUNT, SUM, AVG, MIN, MAX, GROUP BY
 - **test_joins.py**: JOIN operations
 - **test_index.py**: Indexing and query planning
@@ -233,16 +238,17 @@ MiniDB is designed for small to medium datasets:
 - Single-threaded
 - No transactions
 - No foreign key constraints
-- No NULL handling in some edge cases
-- Limited JOIN support (INNER JOIN only)
+- Limited JOIN support (INNER and LEFT JOIN only, no RIGHT JOIN execution)
 
 ## License
 
 MIT License - Use freely for any purpose.
 
 ## Contributing
 
-Contributions welcome! Areas for improvement:
+See [CONTRIBUTING.md](CONTRIBUTING.md) for development setup and guidelines.
+
+Areas for improvement:
 
 - B-tree indexes for range queries
 - LEFT/RIGHT OUTER JOIN

main.py

@@ -12,10 +12,6 @@
 - Persistence
 """
 
-import sys
-
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import MiniDB
 
 

minidb/query.py

@@ -1,5 +1,6 @@
 """Query execution engine for MiniDB."""
 
+import re
 from collections import defaultdict
 from typing import Any
 
@@ -241,7 +242,6 @@ def _evaluate_condition(self, row: Row, condition: Condition) -> bool:
 
     def _match_like(self, value: str, pattern: str) -> bool:
         """Match a value against a LIKE pattern."""
-        import re
 
         # Convert SQL LIKE pattern to regex
         # % matches any sequence, _ matches single character
@@ -385,13 +385,8 @@ def sort_key(row):
             return keys
 
         # Sort with direction handling
-        sorted_rows = sorted(rows, key=sort_key)
-
-        # Reverse if DESC
-        if order_by and order_by[0].direction == 'DESC':
-            sorted_rows = sorted(rows, key=sort_key, reverse=True)
-
-        return sorted_rows
+        reverse = bool(order_by and order_by[0].direction == 'DESC')
+        return sorted(rows, key=sort_key, reverse=reverse)
 
     def execute_insert(self, query: InsertQuery) -> int:
         """Execute an INSERT query."""

pyproject.toml

@@ -19,6 +19,7 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
     "Topic :: Database",
     "Typing :: Typed",
 ]

tests/test_aggregations.py

@@ -1,11 +1,7 @@
 """Tests for aggregation functions."""
 
-import sys
-
 import pytest
 
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import Column, ColumnType, MiniDB
 
 

tests/test_crud.py

@@ -1,11 +1,7 @@
 """Tests for INSERT, SELECT, UPDATE, DELETE operations."""
 
-import sys
-
 import pytest
 
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import Column, ColumnType, DuplicateKeyError, MiniDB
 
 

tests/test_database.py

@@ -1,11 +1,7 @@
 """Tests for database lifecycle and table management."""
 
-import sys
-
 import pytest
 
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import Column, ColumnType, MiniDB, TableExistsError, TableNotFoundError
 
 
@@ -99,3 +95,52 @@ def test_drop_table_not_found(self):
 
         with pytest.raises(TableNotFoundError):
             db.drop_table('nonexistent')
+
+    def test_drop_table_sql(self):
+        """Test dropping a table using SQL."""
+        db = MiniDB()
+        db.execute('CREATE TABLE temp (id INTEGER PRIMARY KEY, value STRING)')
+        assert 'temp' in db
+        db.execute('DROP TABLE temp')
+        assert 'temp' not in db
+
+    def test_query_on_non_select(self):
+        """Test that query() raises MiniDBError for non-SELECT statements."""
+        from minidb.errors import MiniDBError
+
+        db = MiniDB()
+        db.execute('CREATE TABLE t (id INTEGER PRIMARY KEY, v STRING)')
+        with pytest.raises(MiniDBError, match='Query did not return rows'):
+            db.query("INSERT INTO t (id, v) VALUES (1, 'x')")
+
+    def test_repr(self):
+        """Test __repr__ on MiniDB."""
+        db = MiniDB()
+        assert repr(db) == 'MiniDB()'
+        db.execute('CREATE TABLE users (id INTEGER PRIMARY KEY)')
+        db.execute('INSERT INTO users (id) VALUES (1)')
+        assert 'users(1 rows)' in repr(db)
+
+    def test_insert_into_nonexistent_table(self):
+        """Test INSERT into a table that does not exist raises error."""
+        db = MiniDB()
+        with pytest.raises(TableNotFoundError):
+            db.execute('INSERT INTO ghost (id) VALUES (1)')
+
+    def test_update_nonexistent_table(self):
+        """Test UPDATE on a table that does not exist raises error."""
+        db = MiniDB()
+        with pytest.raises(TableNotFoundError):
+            db.execute('UPDATE ghost SET id = 1')
+
+    def test_delete_from_nonexistent_table(self):
+        """Test DELETE from a table that does not exist raises error."""
+        db = MiniDB()
+        with pytest.raises(TableNotFoundError):
+            db.execute('DELETE FROM ghost')
+
+    def test_select_from_nonexistent_table(self):
+        """Test SELECT from a table that does not exist raises error."""
+        db = MiniDB()
+        with pytest.raises(TableNotFoundError):
+            db.query('SELECT * FROM ghost')

tests/test_index.py

@@ -1,9 +1,5 @@
 """Tests for indexing and query planning."""
 
-import sys
-
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import Column, ColumnType, HashIndex, MiniDB
 from minidb.planner import QueryPlanner, ScanType
 

tests/test_joins.py

@@ -1,11 +1,7 @@
 """Tests for JOIN operations."""
 
-import sys
-
 import pytest
 
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import Column, ColumnType, MiniDB
 
 

tests/test_performance.py

@@ -1,12 +1,9 @@
 """Tests for performance with large datasets."""
 
-import sys
 import time
 
 import pytest
 
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import Column, ColumnType, MiniDB
 
 

tests/test_persistence.py

@@ -1,13 +1,10 @@
 """Tests for persistence functionality."""
 
 import os
-import sys
 import tempfile
 
 import pytest
 
-sys.path.insert(0, '/home/sebtardif/MiniDB')
-
 from minidb import Column, ColumnType, MiniDB
 
 
@@ -170,6 +167,46 @@ def test_persistence_file_not_found(self):
         with pytest.raises(FileReadError):
             MiniDB.load('/nonexistent/path/to/file.json')
 
+    def test_persistence_version_mismatch(self):
+        """Test loading a file with incompatible version raises error."""
+        import json
+
+        from minidb.errors import VersionMismatchError
+
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            filepath = f.name
+            json.dump({'version': '99.0', 'tables': {}}, f)
+
+        try:
+            with pytest.raises(VersionMismatchError) as exc_info:
+                MiniDB.load(filepath)
+            assert '99.0' in str(exc_info.value)
+        finally:
+            os.unlink(filepath)
+
+    def test_persistence_invalid_json(self):
+        """Test loading a file with invalid JSON raises error."""
+        from minidb.errors import FileReadError
+
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            filepath = f.name
+            f.write('not valid json {{{')
+
+        try:
+            with pytest.raises(FileReadError) as exc_info:
+                MiniDB.load(filepath)
+            assert 'Invalid JSON' in str(exc_info.value)
+        finally:
+            os.unlink(filepath)
+
+    def test_persistence_write_to_readonly_path(self):
+        """Test saving to an unwritable path raises error."""
+        from minidb.errors import FileWriteError
+
+        db = MiniDB()
+        with pytest.raises(FileWriteError):
+            db.save('/nonexistent/directory/file.json')
+
     def test_json_format_readable(self):
         """Test that saved JSON is human-readable."""
         db = MiniDB()