From b1b21bdac5c39e11b3293a28916fb4f62e70832d Mon Sep 17 00:00:00 2001
From: Dmitry Gozman <dgozman@gmail.com>
Date: Tue, 29 Nov 2022 16:02:11 -0800
Subject: [PATCH] fix(shards): zero-sized shard should not include all tests
 (#19148)

Fixes #19073.
---
 packages/playwright-test/src/runner.ts | 10 +++++++++-
 tests/playwright-test/shard.spec.ts    |  9 +++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/packages/playwright-test/src/runner.ts b/packages/playwright-test/src/runner.ts
index 8ceb9a0cd9..6bd73a9709 100644
--- a/packages/playwright-test/src/runner.ts
+++ b/packages/playwright-test/src/runner.ts
@@ -431,7 +431,15 @@ export class Runner {
     projectSetupGroups.length = 0;
     projectSetupGroups.push(...shardSetupGroups);
 
-    filterSuiteWithOnlySemantics(rootSuite, () => false, test => shardTests.has(test));
+    if (!shardTests.size) {
+      // Filtering with "only semantics" does not work when we have zero tests - it leaves all the tests.
+      // We need an empty suite in this case.
+      rootSuite._entries = [];
+      rootSuite.suites = [];
+      rootSuite.tests = [];
+    } else {
+      filterSuiteWithOnlySemantics(rootSuite, () => false, test => shardTests.has(test));
+    }
   }
 
   private async _run(options: RunOptions): Promise<FullResult> {
diff --git a/tests/playwright-test/shard.spec.ts b/tests/playwright-test/shard.spec.ts
index fc84d8402c..8eb018e8bd 100644
--- a/tests/playwright-test/shard.spec.ts
+++ b/tests/playwright-test/shard.spec.ts
@@ -63,6 +63,15 @@ test('should respect shard=2/2', async ({ runInlineTest }) => {
   expect(result.output).toContain('test5-done');
 });
 
+test('should not produce skipped tests for zero-sized shards', async ({ runInlineTest }) => {
+  const result = await runInlineTest(tests, { shard: '10/10' });
+  expect(result.exitCode).toBe(0);
+  expect(result.passed).toBe(0);
+  expect(result.failed).toBe(0);
+  expect(result.skipped).toBe(0);
+  expect(result.output).not.toContain('-done');
+});
+
 test('should respect shard=1/2 in config', async ({ runInlineTest }) => {
   const result = await runInlineTest({
     ...tests,