From 025e65a1a7562b02b0b576329466e3d42557c300 Mon Sep 17 00:00:00 2001
From: jianmosier <19506927+jianmosier@users.noreply.github.com>
Date: Wed, 20 May 2026 20:20:13 +0800
Subject: [PATCH] test: cover trace tree binary search bounds

---
 test/binSearch.test.ts     | 32 +++++++++++++++++++++++++++
 ui/components/TreeNode.vue |  2 +-
 ui/src/binSearch.ts        | 44 ++++++++++++++++----------------------
 3 files changed, 51 insertions(+), 27 deletions(-)
 create mode 100644 test/binSearch.test.ts

diff --git a/test/binSearch.test.ts b/test/binSearch.test.ts
new file mode 100644
index 0000000..d506022
--- /dev/null
+++ b/test/binSearch.test.ts
@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest'
+import { binSearch } from '../ui/src/binSearch'
+
+describe('binSearch', () => {
+  const rows = [
+    { ts: 10, label: 'a' },
+    { ts: 20, label: 'b' },
+    { ts: 30, label: 'c' },
+    { ts: 40, label: 'd' },
+  ]
+
+  it('returns items inside the inclusive range', () => {
+    expect(binSearch(rows, 20, 30).map(row => row.label)).toEqual(['b', 'c'])
+  })
+
+  it('handles ranges that start before or end after the array', () => {
+    expect(binSearch(rows, 0, 20).map(row => row.label)).toEqual(['a', 'b'])
+    expect(binSearch(rows, 30, 100).map(row => row.label)).toEqual(['c', 'd'])
+  })
+
+  it('returns an empty array when the range misses the array', () => {
+    expect(binSearch(rows, 0, 5)).toEqual([])
+    expect(binSearch(rows, 45, 100)).toEqual([])
+  })
+
+  it('handles empty, single-item, and invalid ranges', () => {
+    expect(binSearch([], 0, 100)).toEqual([])
+    expect(binSearch([{ ts: 0 }], 0, 0)).toEqual([{ ts: 0 }])
+    expect(binSearch([{ ts: 0 }], 1, 1)).toEqual([])
+    expect(binSearch(rows, 30, 20)).toEqual([])
+  })
+})
diff --git a/ui/components/TreeNode.vue b/ui/components/TreeNode.vue
index 997a094..13660c3 100644
--- a/ui/components/TreeNode.vue
+++ b/ui/components/TreeNode.vue
@@ -22,7 +22,7 @@ function fetchTypes() {
 function gotoPosition() {
   if ('name' in props.tree.line) {
     const { path, pos } = props.tree.line.args ?? { path: undefined, pos: undefined }
-    if (!path || !pos)
+    if (!path || pos === undefined)
       return
 
     sendMessage('gotoPosition', { fileName: path, pos })
diff --git a/ui/src/binSearch.ts b/ui/src/binSearch.ts
index 7e60b01..683626e 100644
--- a/ui/src/binSearch.ts
+++ b/ui/src/binSearch.ts
@@ -1,37 +1,29 @@
 // arr must be sorted by ts
 export function binSearch<T extends { ts: number }>(arr: T[], from: number, to: number): T[] {
   if (arr.length === 0 || from > to)
-    return arr
+    return []
 
-  let idx = Math.trunc(arr.length / 2)
-  let upperBound = arr.length
-  let lowerBound = 0
+  let start = 0
+  let end = arr.length
 
-  while (arr[idx].ts <= to) {
-    upperBound = idx
-    idx = Math.trunc(idx / 2)
+  while (start < end) {
+    const mid = Math.trunc((start + end) / 2)
+    if (arr[mid].ts < from)
+      start = mid + 1
+    else
+      end = mid
   }
 
-  while (arr[idx].ts > to) {
-    lowerBound = idx
-    idx = Math.round(idx + (upperBound - idx) / 2)
-  }
-
-  const endPos = lowerBound
+  const startPos = start
 
-  upperBound = lowerBound
-  lowerBound = 0
-  while (arr[idx].ts > from) {
-    lowerBound = idx
-    idx = Math.round(idx + (upperBound - idx) / 2)
+  end = arr.length
+  while (start < end) {
+    const mid = Math.trunc((start + end) / 2)
+    if (arr[mid].ts <= to)
+      start = mid + 1
+    else
+      end = mid
   }
 
-  while (arr[idx].ts <= from) {
-    upperBound = idx
-    idx = Math.trunc(idx / 2)
-  }
-
-  const startPos = upperBound
-
-  return arr.slice(startPos, endPos + 1)
+  return arr.slice(startPos, start)
 }