Fix flaky partitionPoint test (#8198)

The tests for `partitionPoint` were previously failing when `NaN` or duplicates were present in the array.

# Important Notes
None

app/gui2/src/util/__tests__/array.test.ts

@@ -14,18 +14,26 @@ fcTest.prop({
 })
 
 fcTest.prop({
-  arr: fc
-    .array(fc.float())
-    .map((a) => ({ arr: a.sort((a, b) => a - b), i: Math.floor(Math.random() * a.length) })),
+  arr: fc.array(fc.float({ noNaN: true })).chain((a) => {
+    const sorted = a.sort((a, b) => a - b)
+    return fc.record({
+      arr: fc.constant(sorted),
+      i: fc.nat({ max: Math.max(sorted.length - 1, 0) }).map((i) => Math.max(0, a.indexOf(a[i]!))),
+    })
+  }),
 })('partitionPoint (ascending)', ({ arr: { arr, i } }) => {
   const target = arr[i]!
   expect(partitionPoint(arr, (n) => n < target)).toEqual(i)
 })
 
 fcTest.prop({
-  arr: fc
-    .array(fc.float())
-    .map((a) => ({ arr: a.sort((a, b) => b - a), i: Math.floor(Math.random() * a.length) })),
+  arr: fc.array(fc.float({ noNaN: true })).chain((a) => {
+    const sorted = a.sort((a, b) => b - a)
+    return fc.record({
+      arr: fc.constant(sorted),
+      i: fc.nat({ max: Math.max(sorted.length - 1, 0) }).map((i) => Math.max(0, a.indexOf(a[i]!))),
+    })
+  }),
 })('partitionPoint (descending)', ({ arr: { arr, i } }) => {
   const target = arr[i]!
   expect(partitionPoint(arr, (n) => n > target)).toEqual(i)