Phase 3: Outcome storage

- Add RandomNumberOutcome model to models.py
- Update worker.py to execute job logic:
  - Generate random number 0-100
  - Record execution duration
  - Store outcome in database
- Add test_jobs.py with unit tests for job handler logic

backend/tests/test_jobs.py

@@ -0,0 +1,173 @@
+"""Tests for job handler logic."""
+
+import json
+from contextlib import asynccontextmanager
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+
+def create_mock_pool(mock_conn: AsyncMock) -> MagicMock:
+    """Create a mock asyncpg pool with proper async context manager behavior."""
+    mock_pool = MagicMock()
+
+    @asynccontextmanager
+    async def mock_acquire():
+        yield mock_conn
+
+    mock_pool.acquire = mock_acquire
+    return mock_pool
+
+
+class TestRandomNumberJobHandler:
+    """Tests for the random number job handler logic."""
+
+    @pytest.mark.asyncio
+    async def test_generates_random_number_in_range(self):
+        """Verify random number is in range [0, 100]."""
+        from worker import process_random_number_job
+
+        # Create mock job
+        job = MagicMock()
+        job.id = 123
+        job.payload = json.dumps({"user_id": 1}).encode()
+
+        # Create mock db pool
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        # Run the job handler
+        await process_random_number_job(job, mock_pool)
+
+        # Verify execute was called
+        mock_conn.execute.assert_called_once()
+        call_args = mock_conn.execute.call_args
+
+        # Extract the value argument (position 3 in the args)
+        # Args: (query, job_id, user_id, value, duration_ms, status)
+        value = call_args[0][3]
+
+        assert 0 <= value <= 100, f"Value {value} is not in range [0, 100]"
+
+    @pytest.mark.asyncio
+    async def test_stores_correct_user_id(self):
+        """Verify the correct user_id is stored in the outcome."""
+        from worker import process_random_number_job
+
+        user_id = 42
+
+        job = MagicMock()
+        job.id = 123
+        job.payload = json.dumps({"user_id": user_id}).encode()
+
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        await process_random_number_job(job, mock_pool)
+
+        mock_conn.execute.assert_called_once()
+        call_args = mock_conn.execute.call_args
+
+        # Args: (query, job_id, user_id, value, duration_ms, status)
+        stored_user_id = call_args[0][2]
+        assert stored_user_id == user_id
+
+    @pytest.mark.asyncio
+    async def test_stores_job_id(self):
+        """Verify the job_id is stored in the outcome."""
+        from worker import process_random_number_job
+
+        job_id = 456
+
+        job = MagicMock()
+        job.id = job_id
+        job.payload = json.dumps({"user_id": 1}).encode()
+
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        await process_random_number_job(job, mock_pool)
+
+        mock_conn.execute.assert_called_once()
+        call_args = mock_conn.execute.call_args
+
+        # Args: (query, job_id, user_id, value, duration_ms, status)
+        stored_job_id = call_args[0][1]
+        assert stored_job_id == job_id
+
+    @pytest.mark.asyncio
+    async def test_stores_status_completed(self):
+        """Verify the status is set to 'completed'."""
+        from worker import process_random_number_job
+
+        job = MagicMock()
+        job.id = 123
+        job.payload = json.dumps({"user_id": 1}).encode()
+
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        await process_random_number_job(job, mock_pool)
+
+        mock_conn.execute.assert_called_once()
+        call_args = mock_conn.execute.call_args
+
+        # Args: (query, job_id, user_id, value, duration_ms, status)
+        status = call_args[0][5]
+        assert status == "completed"
+
+    @pytest.mark.asyncio
+    async def test_records_duration_ms(self):
+        """Verify duration_ms is recorded (should be >= 0)."""
+        from worker import process_random_number_job
+
+        job = MagicMock()
+        job.id = 123
+        job.payload = json.dumps({"user_id": 1}).encode()
+
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        await process_random_number_job(job, mock_pool)
+
+        mock_conn.execute.assert_called_once()
+        call_args = mock_conn.execute.call_args
+
+        # Args: (query, job_id, user_id, value, duration_ms, status)
+        duration_ms = call_args[0][4]
+        assert isinstance(duration_ms, int)
+        assert duration_ms >= 0
+
+    @pytest.mark.asyncio
+    async def test_missing_user_id_does_not_insert(self):
+        """Verify no insert happens if user_id is missing from payload."""
+        from worker import process_random_number_job
+
+        job = MagicMock()
+        job.id = 123
+        job.payload = json.dumps({}).encode()  # Missing user_id
+
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        await process_random_number_job(job, mock_pool)
+
+        # Should not have called execute
+        mock_conn.execute.assert_not_called()
+
+    @pytest.mark.asyncio
+    async def test_empty_payload_does_not_insert(self):
+        """Verify no insert happens with empty payload."""
+        from worker import process_random_number_job
+
+        job = MagicMock()
+        job.id = 123
+        job.payload = None
+
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        await process_random_number_job(job, mock_pool)
+
+        # Should not have called execute
+        mock_conn.execute.assert_not_called()