docs: clarify that slow tests are about files (#10134)

docs/src/test-advanced-js.md

@@ -40,7 +40,7 @@ These options would be typically different between local development and CI oper
 - `projects: Project[]` - Multiple [projects](#projects) configuration.
 - `quiet: boolean` - Whether to suppress stdout and stderr from the tests.
 - `reporter: 'list' | 'line' | 'dot' | 'json' | 'junit' | 'github' | 'html' | 'null'` - The reporter to use. See [reporters](./test-reporters.md) for details.
-- `reportSlowTests: { max: number, threshold: number } | null` - Whether to report slow tests. When `null`, slow tests are not reported. Otherwise, tests that took more than `threshold` milliseconds are reported as slow, but no more than `max` number of them. Passing zero as `max` reports all slow tests that exceed the threshold.
+- `reportSlowTests: { max: number, threshold: number } | null` - Whether to report slow test files. When `null`, slow test files are not reported. Otherwise, test files that took more than `threshold` milliseconds are reported as slow, but no more than `max` number of them. Passing zero as `max` reports all test files that exceed the threshold.
 - `shard: { total: number, current: number } | null` - [Shard](./test-parallel.md#shard-tests-between-multiple-machines) information.
 - `updateSnapshots: boolean` - Whether to update expected snapshots with the actual results produced by the test run.
 - `workers: number` - The maximum number of concurrent worker processes to use for parallelizing tests.

docs/src/test-api/class-testconfig.md

@@ -358,12 +358,12 @@ export default config;
 
 ## property: TestConfig.reportSlowTests
 - type: <[Object]>
-  - `max` <[int]> The maximum number of slow tests to report. Defaults to `5`.
+  - `max` <[int]> The maximum number of slow test files to report. Defaults to `5`.
   - `threshold` <[float]> Test duration in milliseconds that is considered slow. Defaults to 15 seconds.
 
-Whether to report slow tests. Pass `null` to disable this feature.
+Whether to report slow test files. Pass `null` to disable this feature.
 
-Tests that took more than `threshold` milliseconds are considered slow, and the slowest ones are reported, no more than `max` number of them. Passing zero as `max` reports all slow tests that exceed the threshold.
+Test files that took more than `threshold` milliseconds are considered slow, and the slowest ones are reported, no more than `max` number of them. Passing zero as `max` reports all test files that exceed the threshold.
 
 ## property: TestConfig.retries
 - type: <[int]>

packages/playwright-test/src/reporters/base.ts

@@ -198,9 +198,12 @@ export class BaseReporter implements Reporter  {
   }
 
   private _printSlowTests() {
-    this.getSlowTests().forEach(([file, duration]) => {
-      console.log(colors.yellow('  Slow test: ') + file + colors.yellow(` (${milliseconds(duration)})`));
+    const slowTests = this.getSlowTests();
+    slowTests.forEach(([file, duration]) => {
+      console.log(colors.yellow('  Slow test file: ') + file + colors.yellow(` (${milliseconds(duration)})`));
     });
+    if (slowTests.length)
+      console.log(colors.yellow('  Consider splitting slow test files to speed up parallel execution'));
   }
 
   private _printSummary(summary: string) {

packages/playwright-test/types/test.d.ts

@@ -546,10 +546,10 @@ interface TestConfig {
    */
   reporter?: LiteralUnion<'list'|'dot'|'line'|'github'|'json'|'junit'|'null'|'html', string> | ReporterDescription[];
   /**
-   * Whether to report slow tests. Pass `null` to disable this feature.
+   * Whether to report slow test files. Pass `null` to disable this feature.
    *
-   * Tests that took more than `threshold` milliseconds are considered slow, and the slowest ones are reported, no more than
-   * `max` number of them. Passing zero as `max` reports all slow tests that exceed the threshold.
+   * Test files that took more than `threshold` milliseconds are considered slow, and the slowest ones are reported, no more
+   * than `max` number of them. Passing zero as `max` reports all test files that exceed the threshold.
    */
   reportSlowTests?: ReportSlowTests;
   /**
@@ -965,10 +965,10 @@ export interface FullConfig<TestArgs = {}, WorkerArgs = {}> {
    */
   reporter: ReporterDescription[];
   /**
-   * Whether to report slow tests. Pass `null` to disable this feature.
+   * Whether to report slow test files. Pass `null` to disable this feature.
    *
-   * Tests that took more than `threshold` milliseconds are considered slow, and the slowest ones are reported, no more than
-   * `max` number of them. Passing zero as `max` reports all slow tests that exceed the threshold.
+   * Test files that took more than `threshold` milliseconds are considered slow, and the slowest ones are reported, no more
+   * than `max` number of them. Passing zero as `max` reports all test files that exceed the threshold.
    */
   reportSlowTests: ReportSlowTests;
   rootDir: string;

tests/playwright-test/reporter-base.spec.ts

@@ -124,14 +124,15 @@ test('should print slow tests', async ({ runInlineTest }) => {
   });
   expect(result.exitCode).toBe(0);
   expect(result.passed).toBe(8);
-  expect(stripAscii(result.output)).toContain(`Slow test: [foo] › dir${path.sep}a.test.js (`);
-  expect(stripAscii(result.output)).toContain(`Slow test: [bar] › dir${path.sep}a.test.js (`);
-  expect(stripAscii(result.output)).toContain(`Slow test: [baz] › dir${path.sep}a.test.js (`);
-  expect(stripAscii(result.output)).toContain(`Slow test: [qux] › dir${path.sep}a.test.js (`);
-  expect(stripAscii(result.output)).not.toContain(`Slow test: [foo] › dir${path.sep}b.test.js (`);
-  expect(stripAscii(result.output)).not.toContain(`Slow test: [bar] › dir${path.sep}b.test.js (`);
-  expect(stripAscii(result.output)).not.toContain(`Slow test: [baz] › dir${path.sep}b.test.js (`);
-  expect(stripAscii(result.output)).not.toContain(`Slow test: [qux] › dir${path.sep}b.test.js (`);
+  expect(stripAscii(result.output)).toContain(`Slow test file: [foo] › dir${path.sep}a.test.js (`);
+  expect(stripAscii(result.output)).toContain(`Slow test file: [bar] › dir${path.sep}a.test.js (`);
+  expect(stripAscii(result.output)).toContain(`Slow test file: [baz] › dir${path.sep}a.test.js (`);
+  expect(stripAscii(result.output)).toContain(`Slow test file: [qux] › dir${path.sep}a.test.js (`);
+  expect(stripAscii(result.output)).toContain(`Consider splitting slow test files to speed up parallel execution`);
+  expect(stripAscii(result.output)).not.toContain(`Slow test file: [foo] › dir${path.sep}b.test.js (`);
+  expect(stripAscii(result.output)).not.toContain(`Slow test file: [bar] › dir${path.sep}b.test.js (`);
+  expect(stripAscii(result.output)).not.toContain(`Slow test file: [baz] › dir${path.sep}b.test.js (`);
+  expect(stripAscii(result.output)).not.toContain(`Slow test file: [qux] › dir${path.sep}b.test.js (`);
 });
 
 test('should not print slow tests', async ({ runInlineTest }) => {