diff --git a/intelligence/deepdive/tests/test_aggregator.py b/intelligence/deepdive/tests/test_aggregator.py
new file mode 100644
index 0000000..e2f641d
--- /dev/null
+++ b/intelligence/deepdive/tests/test_aggregator.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""Tests for Phase 1: Source Aggregation"""
+
+import asyncio
+import pytest
+from datetime import datetime, timedelta
+from pathlib import Path
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+from pipeline import RSSAggregator, FeedItem
+
+
+class TestRSSAggregator:
+    """Test suite for RSS aggregation."""
+    
+    @pytest.fixture
+    def aggregator(self, tmp_path):
+        return RSSAggregator(cache_dir=tmp_path)
+    
+    @pytest.mark.asyncio
+    async def test_fetch_arxiv_cs_ai(self, aggregator):
+        """Test fetching real arXiv cs.AI feed."""
+        items = await aggregator.fetch_feed(
+            url="http://export.arxiv.org/rss/cs.AI",
+            name="test_arxiv",
+            max_items=5
+        )
+        
+        assert len(items) > 0, "Should fetch items from arXiv"
+        assert all(isinstance(i, FeedItem) for i in items)
+        assert all(i.title for i in items)
+        assert all(i.url.startswith("http") for i in items)
+        print(f"Fetched {len(items)} items from arXiv cs.AI")
+    
+    @pytest.mark.asyncio
+    async def test_fetch_all_sources(self, aggregator):
+        """Test fetching from multiple sources."""
+        sources = [
+            {"name": "arxiv_ai", "url": "http://export.arxiv.org/rss/cs.AI", "max_items": 3},
+            {"name": "arxiv_cl", "url": "http://export.arxiv.org/rss/cs.CL", "max_items": 3},
+        ]
+        
+        since = datetime.utcnow() - timedelta(hours=48)
+        items = await aggregator.fetch_all(sources, since=since)
+        
+        assert len(items) > 0
+        # Check deduplication
+        hashes = [i.content_hash for i in items]
+        assert len(hashes) == len(set(hashes)), "Should deduplicate items"
+    
+    def test_content_hash_consistency(self):
+        """Test that identical content produces identical hashes."""
+        agg = RSSAggregator()
+        h1 = agg._compute_hash("Test content")
+        h2 = agg._compute_hash("Test content")
+        h3 = agg._compute_hash("Different content")
+        
+        assert h1 == h2
+        assert h1 != h3
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])