Reduce snapshot batch test fixture sizes (#28381)

Author: kitlangton

packages/opencode/test/snapshot/snapshot.test.ts

@@ -15,6 +15,9 @@ const it = testEffect(Layer.mergeAll(Snapshot.defaultLayer, AppFileSystem.defaul
 // with path.join (which produces \ on Windows) then normalizes back to /.
 // This helper does the same for expected values so assertions match cross-platform.
 const fwd = (...parts: string[]) => path.join(...parts).replaceAll("\\", "/")
+const SNAPSHOT_BATCH_BOUNDARY = 100
+const OVER_BATCH_COUNT = SNAPSHOT_BATCH_BOUNDARY + 1
+const MIXED_BATCH_GROUP_COUNT = Math.ceil(OVER_BATCH_COUNT / 4)
 
 afterEach(async () => {
   await disposeAllInstances()
@@ -802,7 +805,7 @@ it.instance(
   Effect.gen(function* () {
     const tmp = yield* bootstrap()
     const snapshot = yield* Snapshot.Service
-    const ids = Array.from({ length: 60 }, (_, i) => i.toString().padStart(3, "0"))
+    const ids = Array.from({ length: MIXED_BATCH_GROUP_COUNT }, (_, i) => i.toString().padStart(3, "0"))
     const mod = ids.map((id) => fwd(tmp.path, "mix", `${id}-mod.txt`))
     const del = ids.map((id) => fwd(tmp.path, "mix", `${id}-del.txt`))
     const add = ids.map((id) => fwd(tmp.path, "mix", `${id}-add.txt`))
@@ -862,7 +865,7 @@ it.instance(
   Effect.gen(function* () {
     const tmp = yield* bootstrap()
     const snapshot = yield* Snapshot.Service
-    const ids = Array.from({ length: 140 }, (_, i) => i.toString().padStart(3, "0"))
+    const ids = Array.from({ length: OVER_BATCH_COUNT }, (_, i) => i.toString().padStart(3, "0"))
     yield* mkdirp(`${tmp.path}/order`)
     yield* Effect.all(
       ids.map((id) => write(`${tmp.path}/order/${id}.txt`, `before-${id}`)),
@@ -1090,8 +1093,8 @@ it.instance(
   Effect.gen(function* () {
     const tmp = yield* bootstrap()
     const snapshot = yield* Snapshot.Service
-    const base = Array.from({ length: 140 }, (_, i) => fwd(tmp.path, "batch", `${i}.txt`))
-    const fresh = Array.from({ length: 140 }, (_, i) => fwd(tmp.path, "fresh", `${i}.txt`))
+    const base = Array.from({ length: OVER_BATCH_COUNT }, (_, i) => fwd(tmp.path, "batch", `${i}.txt`))
+    const fresh = [fwd(tmp.path, "fresh", "0.txt")]
     yield* mkdirp(`${tmp.path}/batch`)
     yield* mkdirp(`${tmp.path}/fresh`)
     yield* Effect.all(

perf/test-suite.md

@@ -82,6 +82,7 @@ Repeated setup work, long sleeps/timeouts, serial integration tests, filesystem/
 | Local plugin and subagent config fixtures can use Effect-aware instance fixtures                          | Migrated scoped npm plugin and custom subagent markdown cases to `it.instance`                 | 2.37s     | 1.67s   | keep     | Single baseline before edit; after median from three sequential reruns (1.66, 1.67, 1.67).                                       |
 | MCP merge config cases can use Effect-aware instance fixtures                                             | Migrated three MCP merge/override cases to `it.instance`                                       | 1.98s     | 1.95s   | keep     | Neutral timing within noise; removes manual `tmpdir` + `withTestInstance` setup from isolated filesystem-only config cases.      |
 | Remaining legacy tools config cases can use Effect-aware instance fixtures                                | Migrated allow/deny legacy `tools` permission cases to `it.instance`                           | 2.65s     | 1.90s   | keep     | Single baseline before edit; after median from three sequential reruns (2.58, 1.90, 1.90).                                       |
+| Oversized snapshot batch tests only need to cross the 100-file boundary                                   | Reduced large diff/revert fixture sizes while keeping each case above the batch boundary       | 4.32s     | 3.66s   | keep     | Three affected snapshot tests; after median from three reruns (4.32, 3.66, 3.66) while still crossing the 100-file boundary.     |
 
 ## Profiling Results