From e0a8d59fef67f82259f85c8a95c8a0efa557b1e3 Mon Sep 17 00:00:00 2001
From: Karl Power <karl.power@clickhouse.com>
Date: Fri, 20 Feb 2026 15:57:15 +0100
Subject: [PATCH] tests for buildJSONExtractQuery

---
 .../src/components/DBRowJsonViewer.test.tsx   | 55 ++++++++++++++++++-
 .../app/src/components/DBRowJsonViewer.tsx    |  2 +-
 2 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/packages/app/src/components/DBRowJsonViewer.test.tsx b/packages/app/src/components/DBRowJsonViewer.test.tsx
index 22fe2af8..3598e3ae 100644
--- a/packages/app/src/components/DBRowJsonViewer.test.tsx
+++ b/packages/app/src/components/DBRowJsonViewer.test.tsx
@@ -1,7 +1,7 @@
 import React from 'react';
 import { fireEvent, screen, within } from '@testing-library/react';
 
-import { DBRowJsonViewer } from './DBRowJsonViewer';
+import { buildJSONExtractQuery, DBRowJsonViewer } from './DBRowJsonViewer';
 import { RowSidePanelContext } from './DBRowSidePanel';
 
 // Mock Next.js router
@@ -195,4 +195,57 @@ describe('DBRowJsonViewer', () => {
       );
     });
   });
+
+  describe('buildJSONExtractQuery', () => {
+    it('returns null when keyPath equals parsedJsonRootPath (no nested path)', () => {
+      expect(
+        buildJSONExtractQuery(['LogAttributes'], ['LogAttributes']),
+      ).toBeNull();
+    });
+
+    it('returns null when keyPath is shorter than parsedJsonRootPath', () => {
+      expect(buildJSONExtractQuery([], ['LogAttributes'])).toBeNull();
+    });
+
+    it('builds query for single-level path with default JSONExtractString', () => {
+      expect(
+        buildJSONExtractQuery(['LogAttributes', 'field1'], ['LogAttributes']),
+      ).toBe("JSONExtractString(LogAttributes, 'field1')");
+    });
+
+    it('builds query for nested path', () => {
+      expect(
+        buildJSONExtractQuery(
+          ['LogAttributes', 'nested', 'field3'],
+          ['LogAttributes'],
+        ),
+      ).toBe("JSONExtractString(LogAttributes, 'nested', 'field3')");
+    });
+
+    it('uses JSONExtractFloat when specified', () => {
+      expect(
+        buildJSONExtractQuery(
+          ['SpanAttributes', 'count'],
+          ['SpanAttributes'],
+          'JSONExtractFloat',
+        ),
+      ).toBe("JSONExtractFloat(SpanAttributes, 'count')");
+    });
+
+    it('uses JSONExtractBool when specified', () => {
+      expect(
+        buildJSONExtractQuery(
+          ['LogAttributes', 'enabled'],
+          ['LogAttributes'],
+          'JSONExtractBool',
+        ),
+      ).toBe("JSONExtractBool(LogAttributes, 'enabled')");
+    });
+
+    it('handles path segments that look like array indices', () => {
+      expect(
+        buildJSONExtractQuery(['LogAttributes', '0', 'id'], ['LogAttributes']),
+      ).toBe("JSONExtractString(LogAttributes, '0', 'id')");
+    });
+  });
 });
diff --git a/packages/app/src/components/DBRowJsonViewer.tsx b/packages/app/src/components/DBRowJsonViewer.tsx
index 62a950fb..3bdf0d96 100644
--- a/packages/app/src/components/DBRowJsonViewer.tsx
+++ b/packages/app/src/components/DBRowJsonViewer.tsx
@@ -35,7 +35,7 @@ type JSONExtractFn =
   | 'JSONExtractFloat'
   | 'JSONExtractBool';
 
-function buildJSONExtractQuery(
+export function buildJSONExtractQuery(
   keyPath: string[],
   parsedJsonRootPath: string[],
   jsonExtractFn: JSONExtractFn = 'JSONExtractString',