[feature] Added a CLI flag to allow passing without any test files found

.changeset/fair-melons-taste.md

@@ -0,0 +1,6 @@
+---
+'@web/test-runner-core': minor
+'@web/test-runner': minor
+---
+
+Added a command line flag to allow the command to pass when no tests are present.

.gitignore

@@ -17,6 +17,9 @@ coverage/
 npm-debug.log
 yarn-error.log
 
+## environment
+.env*
+
 ## temp folders
 /.tmp/
 

docs/docs/test-runner/cli-and-configuration.md

@@ -114,6 +114,8 @@ interface TestRunnerGroupConfig {
   name: string;
   // globs of files to test in this group, if unset it will be inherited from the main config
   files?: string | string[];
+  // allow tests to pass even if there are no test files found
+  allowPassWithoutTests?: boolean;
   // browsers to test in this group, if unset it will be inherited from the main config
   browsers?: BrowserLauncher[];
   // HTML used for running HTML tests for this group
@@ -127,6 +129,8 @@ interface TestRunnerGroupConfig {
 interface TestRunnerConfig {
   // globs of files to test
   files: string | string[];
+  // allow tests to pass even if there are no test files found
+  allowPassWithoutTests?: boolean;
   // test group configs, can be an array of configs or a string or string array of glob patterns
   // which specify where to find the configs
   groups?: string | string[] | TestRunnerGroupConfig[];

packages/test-runner-core/src/config/TestRunnerCoreConfig.ts

@@ -27,6 +27,7 @@ export interface CoverageConfig {
 export interface TestRunnerCoreConfig {
   rootDir: string;
   files?: string | string[];
+  allowPassWithoutTests?: boolean;
   concurrentBrowsers: number;
   concurrency: number;
 

packages/test-runner-core/src/config/TestRunnerGroupConfig.ts

@@ -5,6 +5,7 @@ export interface TestRunnerGroupConfig {
   name: string;
   configFilePath?: string;
   files?: string | string[];
+  allowPassWithoutTests?: boolean;
   browsers?: BrowserLauncher[];
   testRunnerHtml?: (
     testRunnerImport: string,

packages/test-runner-core/src/runner/TestRunner.ts

@@ -128,6 +128,7 @@ export class TestRunner extends EventEmitter<EventMap> {
     this.pendingSessions.clear();
 
     if (sessionsToRun.length === 0) {
+      this.stop();
       return;
     }
 

packages/test-runner-core/src/runner/createSessionGroups.ts

@@ -26,6 +26,7 @@ export function createTestSessions(
     groups.push({
       name: 'default',
       files: config.files,
+      allowPassWithoutTests: config.allowPassWithoutTests,
       browsers: config.browsers,
     });
   }
@@ -52,6 +53,10 @@ export function createTestSessions(
       mergedGroupConfig.files = groupConfig.files;
     }
 
+    if (groupConfig.allowPassWithoutTests != null) {
+        mergedGroupConfig.allowPassWithoutTests = groupConfig.allowPassWithoutTests;
+    }
+
     if (groupConfig.testRunnerHtml != null) {
       mergedGroupConfig.testRunnerHtml = groupConfig.testRunnerHtml;
     }
@@ -71,7 +76,7 @@ export function createTestSessions(
       // C:/foo/bar -> C:\foo\bar
       .map(testFile => path.normalize(testFile));
 
-    if (testFilesForGroup.length === 0) {
+    if (testFilesForGroup.length === 0 && !group.allowPassWithoutTests) {
       throw new Error(`Could not find any test files with pattern(s): ${group.files}`);
     }
 
@@ -112,7 +117,7 @@ export function createTestSessions(
     }
   }
 
-  if (testFiles.size === 0 || testSessions.length === 0) {
+  if ((testFiles.size === 0 || testSessions.length === 0) && !config.allowPassWithoutTests) {
     throw new Error('Did not find any tests to run.');
   }
 

packages/test-runner/src/config/parseConfig.ts

@@ -188,8 +188,10 @@ export async function parseConfig(
       // we can improve this by relying only on groups inside the test runner itself
       if (groupConfig.files == null) {
         groupConfig.files = finalConfig.files;
+        groupConfig.allowPassWithoutTests = finalConfig.allowPassWithoutTests;
       }
       finalConfig.files = undefined;
+      finalConfig.allowPassWithoutTests = undefined;
 
       groupConfigs = [groupConfig];
     }

packages/test-runner/src/config/readCliArgs.ts

@@ -9,6 +9,7 @@ export interface TestRunnerCliArgs
     Pick<
       TestRunnerConfig,
       | 'files'
+      | 'allowPassWithoutTests'
       | 'rootDir'
       | 'watch'
       | 'coverage'
@@ -41,6 +42,11 @@ const options: OptionDefinition[] = [
     defaultOption: true,
     description: 'Test files to run',
   },
+  {
+    name: 'allowPassWithoutTests',
+    type: Boolean,
+    description: 'Allow pass without any tests',
+  },
   {
     name: 'root-dir',
     type: String,