Consolidate duplicate test data

benchmarks/test_data.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <string>
+
+namespace weaseldb::test_data {
+
+// Sample JSON strings of varying complexity for benchmarking and testing
+// Declarations only - definitions in test_data.cpp to avoid ODR violations
+extern const std::string SIMPLE_JSON;
+extern const std::string MEDIUM_JSON;
+extern const std::string COMPLEX_JSON;
+
+// Generate a large JSON with many operations for stress testing
+std::string generate_large_json(int num_operations);
+
+} // namespace weaseldb::test_data