feat(@schematics/angular): add migrate-karma-to-vitest update migration

packages/schematics/angular/migrations/migrate-karma-to-vitest/constants.ts

@@ -0,0 +1,44 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+export const SUPPORTED_REPORTERS = new Set([
+  'default',
+  'verbose',
+  'dots',
+  'json',
+  'junit',
+  'tap',
+  'tap-flat',
+  'html',
+]);
+
+export const SUPPORTED_COVERAGE_REPORTERS = new Set([
+  'html',
+  'lcov',
+  'lcovonly',
+  'text',
+  'text-summary',
+  'cobertura',
+  'json',
+  'json-summary',
+]);
+
+export const BUILD_OPTIONS_KEYS = [
+  'assets',
+  'styles',
+  'scripts',
+  'polyfills',
+  'inlineStyleLanguage',
+  'stylePreprocessorOptions',
+  'externalDependencies',
+  'loader',
+  'define',
+  'fileReplacements',
+  'webWorkerTsConfig',
+  'aot',
+];

packages/schematics/angular/migrations/migrate-karma-to-vitest/karma-processor.ts

@@ -0,0 +1,167 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import type { json } from '@angular-devkit/core';
+import { SchematicContext, Tree } from '@angular-devkit/schematics';
+import { KarmaConfigAnalysis, analyzeKarmaConfig } from '../karma/karma-config-analyzer';
+import { compareKarmaConfigToDefault, hasDifferences } from '../karma/karma-config-comparer';
+import { SUPPORTED_COVERAGE_REPORTERS, SUPPORTED_REPORTERS } from './constants';
+
+function extractReporters(
+  analysis: KarmaConfigAnalysis,
+  options: Record<string, json.JsonValue | undefined>,
+  projectName: string,
+  context: SchematicContext,
+): void {
+  const reporters = analysis.settings.get('reporters');
+  if (Array.isArray(reporters)) {
+    const mappedReporters: string[] = [];
+    for (const r of reporters) {
+      if (typeof r === 'string') {
+        if (r === 'progress') {
+          mappedReporters.push('default');
+        } else if (r === 'kjhtml') {
+          context.logger.warn(
+            `Project "${projectName}" uses the "kjhtml" reporter. ` +
+              `This has not been automatically mapped. ` +
+              `For an interactive test UI in Vitest, consider setting the "ui" option to true in your test target options ` +
+              `and installing "@vitest/ui".`,
+          );
+        } else if (SUPPORTED_REPORTERS.has(r)) {
+          mappedReporters.push(r);
+        } else {
+          context.logger.warn(
+            `Project "${projectName}" uses a custom Karma reporter "${r}". ` +
+              `This reporter cannot be automatically mapped to Vitest. ` +
+              `Please check the Vitest documentation for equivalent reporters.`,
+          );
+        }
+      } else {
+        context.logger.warn(
+          `Project "${projectName}" has a non-string reporter in Karma config. ` +
+            `This cannot be automatically mapped to Vitest.`,
+        );
+      }
+    }
+    if (mappedReporters.length > 0) {
+      options['reporters'] = [...new Set(mappedReporters)];
+    }
+  }
+}
+
+function extractCoverageSettings(
+  analysis: KarmaConfigAnalysis,
+  options: Record<string, json.JsonValue | undefined>,
+  projectName: string,
+  context: SchematicContext,
+): void {
+  const coverageReporter = analysis.settings.get('coverageReporter');
+  if (typeof coverageReporter !== 'object' || coverageReporter === null) {
+    return;
+  }
+
+  // Extract coverage reporters
+  const covReporters = (coverageReporter as Record<string, unknown>)['reporters'];
+  if (Array.isArray(covReporters)) {
+    const mappedCovReporters: string[] = [];
+    for (const r of covReporters) {
+      let type: string | undefined;
+      if (typeof r === 'object' && r !== null && 'type' in r) {
+        if (typeof r['type'] === 'string') {
+          type = r['type'];
+        }
+      } else if (typeof r === 'string') {
+        type = r;
+      }
+
+      if (type) {
+        if (SUPPORTED_COVERAGE_REPORTERS.has(type)) {
+          mappedCovReporters.push(type);
+        } else {
+          context.logger.warn(
+            `Project "${projectName}" uses a custom coverage reporter "${type}". ` +
+              `This reporter cannot be automatically mapped to Vitest. ` +
+              `Please check the Vitest documentation for equivalent coverage reporters.`,
+          );
+        }
+      }
+    }
+    if (mappedCovReporters.length > 0) {
+      options['coverageReporters'] = [...new Set(mappedCovReporters)];
+    }
+  }
+
+  // Extract coverage thresholds
+  const check = (coverageReporter as Record<string, unknown>)['check'];
+  if (typeof check === 'object' && check !== null) {
+    const global = (check as Record<string, unknown>)['global'];
+    if (typeof global === 'object' && global !== null) {
+      const thresholds: Record<string, number> = {};
+      const keys = ['statements', 'branches', 'functions', 'lines'];
+      for (const key of keys) {
+        const value = (global as Record<string, unknown>)[key];
+        if (typeof value === 'number') {
+          thresholds[key] = value;
+        }
+      }
+      if (Object.keys(thresholds).length > 0) {
+        options['coverageThresholds'] = {
+          ...thresholds,
+          perFile: false,
+        };
+      }
+    }
+  }
+}
+
+export async function processKarmaConfig(
+  karmaConfig: string,
+  options: Record<string, json.JsonValue | undefined>,
+  projectName: string,
+  context: SchematicContext,
+  tree: Tree,
+  removableKarmaConfigs: Map<string, boolean>,
+  needDevkitPlugin: boolean,
+  manualMigrationFiles: string[],
+): Promise<void> {
+  if (tree.exists(karmaConfig)) {
+    const content = tree.readText(karmaConfig);
+    const analysis = analyzeKarmaConfig(content);
+
+    extractReporters(analysis, options, projectName, context);
+    extractCoverageSettings(analysis, options, projectName, context);
+
+    let isRemovable = removableKarmaConfigs.get(karmaConfig);
+    if (isRemovable === undefined) {
+      if (analysis.hasUnsupportedValues) {
+        isRemovable = false;
+      } else {
+        const diff = await compareKarmaConfigToDefault(
+          analysis,
+          projectName,
+          karmaConfig,
+          needDevkitPlugin,
+        );
+        isRemovable = !hasDifferences(diff) && diff.isReliable;
+      }
+      removableKarmaConfigs.set(karmaConfig, isRemovable);
+    }
+
+    if (isRemovable) {
+      tree.delete(karmaConfig);
+    } else {
+      context.logger.warn(
+        `Project "${projectName}" uses a custom Karma configuration file "${karmaConfig}". ` +
+          `Tests have been migrated to use Vitest, but you may need to manually migrate custom settings ` +
+          `from this Karma config to a Vitest config (e.g. vitest.config.ts).`,
+      );
+      manualMigrationFiles.push(karmaConfig);
+    }
+  }
+  delete options['karmaConfig'];
+}