From 3dc77b55c9abe2d8873f163b9223947bfecb2394 Mon Sep 17 00:00:00 2001
From: Ben Limpich <blimpich@expensify.com>
Date: Fri, 9 Jan 2026 16:12:49 -0800
Subject: [PATCH 1/2] update number of chunks codecov uses

---
 codecov.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/codecov.yml b/codecov.yml
index 17cd8f9e567b0..f526f04b2d410 100644
--- a/codecov.yml
+++ b/codecov.yml
@@ -13,8 +13,8 @@ coverage:
 
 codecov:
   notify:
-    # We shard our tests into 3 chunks, so we want CodeCov to wait for 3 builds before commenting
-    after_n_builds: 3
+    # We shard our tests into 8 chunks, so we want CodeCov to wait for 8 builds before commenting
+    after_n_builds: 8
 
 comment:
   require_changes: "coverage_drop OR uncovered_patch"

From a547d6828d1ba2f9a7240135d487b6a645265b4e Mon Sep 17 00:00:00 2001
From: Ben Limpich <blimpich@expensify.com>
Date: Fri, 9 Jan 2026 16:13:02 -0800
Subject: [PATCH 2/2] add test to make sure chunks stay in lock step

---
 tests/unit/codecovConfigTest.ts | 48 +++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 tests/unit/codecovConfigTest.ts

diff --git a/tests/unit/codecovConfigTest.ts b/tests/unit/codecovConfigTest.ts
new file mode 100644
index 0000000000000..24e4f60220737
--- /dev/null
+++ b/tests/unit/codecovConfigTest.ts
@@ -0,0 +1,48 @@
+import fs from 'fs';
+import path from 'path';
+
+/**
+ * Extracts the after_n_builds value from codecov.yml
+ * Expected format: "after_n_builds: 8"
+ */
+function getAfterNBuildsFromCodecov(content: string): number | null {
+    const match = content.match(/after_n_builds:\s*(\d+)/);
+    return match ? parseInt(match[1], 10) : null;
+}
+
+/**
+ * Extracts the chunk array from test.yml workflow
+ * Expected format: "chunk: [1, 2, 3, 4, 5, 6, 7, 8]"
+ */
+function getChunksFromTestWorkflow(content: string): number[] | null {
+    const match = content.match(/chunk:\s*\[([^\]]+)\]/);
+    if (!match) {
+        return null;
+    }
+    const chunksStr = match[1];
+    return chunksStr.split(',').map((chunk) => parseInt(chunk.trim(), 10));
+}
+
+describe('Codecov configuration', () => {
+    test('after_n_builds matches the number of test shards in test.yml', () => {
+        const codecovPath = path.resolve(__dirname, '../../codecov.yml');
+        const testWorkflowPath = path.resolve(__dirname, '../../.github/workflows/test.yml');
+
+        // Read codecov.yml and extract after_n_builds
+        const codecovContent = fs.readFileSync(codecovPath, 'utf-8');
+        const afterNBuilds = getAfterNBuildsFromCodecov(codecovContent);
+
+        // Read test.yml and extract chunk array
+        const testWorkflowContent = fs.readFileSync(testWorkflowPath, 'utf-8');
+        const chunks = getChunksFromTestWorkflow(testWorkflowContent);
+
+        // Validate both values exist
+        expect(afterNBuilds).not.toBeNull();
+        expect(chunks).not.toBeNull();
+        expect(Array.isArray(chunks)).toBe(true);
+
+        // Validate they match
+        const numberOfShards = chunks?.length ?? 0;
+        expect(afterNBuilds).toBe(numberOfShards);
+    });
+});