[jest] refactor config check

package.json

@@ -532,6 +532,7 @@
     "@istanbuljs/schema": "^0.1.2",
     "@jest/console": "^26.6.2",
     "@jest/reporters": "^26.6.2",
+    "@jest/types": "^26",
     "@kbn/ambient-storybook-types": "link:bazel-bin/packages/kbn-ambient-storybook-types",
     "@kbn/ambient-ui-types": "link:bazel-bin/packages/kbn-ambient-ui-types",
     "@kbn/axe-config": "link:bazel-bin/packages/kbn-axe-config",
@@ -1026,10 +1027,12 @@
     "jest-canvas-mock": "^2.3.1",
     "jest-circus": "^26.6.3",
     "jest-cli": "^26.6.3",
+    "jest-config": "^26",
     "jest-diff": "^26.6.2",
     "jest-environment-jsdom": "^26.6.2",
     "jest-environment-jsdom-thirteen": "^1.0.1",
     "jest-raw-loader": "^1.0.1",
+    "jest-runtime": "^26",
     "jest-silent-reporter": "^0.5.0",
     "jest-snapshot": "^26.6.2",
     "jest-specific-snapshot": "2.0.0",

packages/kbn-test/src/jest/configs/get_all_jest_paths.ts

@@ -0,0 +1,74 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import Fs from 'fs';
+import Path from 'path';
+
+import execa from 'execa';
+import minimatch from 'minimatch';
+import { REPO_ROOT } from '@kbn/utils';
+
+// @ts-expect-error jest-preset is necessarily a JS file
+import { testMatch } from '../../../jest-preset';
+
+const UNIT_CONFIG_NAME = 'jest.config.js';
+const INTEGRATION_CONFIG_NAME = 'jest.integration.config.js';
+
+export async function getAllJestPaths() {
+  const proc = await execa('git', ['ls-files', '-comt', '--exclude-standard'], {
+    cwd: REPO_ROOT,
+    stdio: ['ignore', 'pipe', 'pipe'],
+    buffer: true,
+  });
+
+  const testsRe = (testMatch as string[]).map((p) => minimatch.makeRe(p));
+  const classify = (rel: string) => {
+    if (testsRe.some((re) => re.test(rel))) {
+      return 'test' as const;
+    }
+
+    const basename = Path.basename(rel);
+    return basename === UNIT_CONFIG_NAME || basename === INTEGRATION_CONFIG_NAME
+      ? ('config' as const)
+      : undefined;
+  };
+
+  const tests = new Set<string>();
+  const configs = new Set<string>();
+
+  for (const line of proc.stdout.split('\n').map((l) => l.trim())) {
+    if (!line) {
+      continue;
+    }
+
+    const rel = line.slice(2); // trim the single char status from the line
+    const type = classify(rel);
+
+    if (!type) {
+      continue;
+    }
+
+    const set = type === 'test' ? tests : configs;
+    const abs = Path.resolve(REPO_ROOT, rel);
+
+    if (line.startsWith('C ')) {
+      // this line indicates that the previous path is changed in the working tree, so we need to determine if
+      // it was deleted, and if so, remove it from the set we added it to
+      if (!Fs.existsSync(abs)) {
+        set.delete(abs);
+      }
+    } else {
+      set.add(abs);
+    }
+  }
+
+  return {
+    tests,
+    configs,
+  };
+}

packages/kbn-test/src/jest/configs/get_tests_for_config_paths.ts

@@ -0,0 +1,52 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { readConfig } from 'jest-config';
+import { createContext } from 'jest-runtime';
+import { SearchSource } from 'jest';
+import { asyncMapWithLimit } from '@kbn/std';
+
+const EMPTY_ARGV = {
+  $0: '',
+  _: [],
+};
+
+const NO_WARNINGS_CONSOLE = {
+  ...console,
+  warn() {
+    // ignore haste-map warnings
+  },
+};
+
+export interface TestsForConfigPath {
+  path: string;
+  testPaths: Set<string>;
+}
+
+export async function getTestsForConfigPaths(
+  configPaths: Iterable<string>
+): Promise<TestsForConfigPath[]> {
+  return await asyncMapWithLimit(configPaths, 60, async (path) => {
+    const config = await readConfig(EMPTY_ARGV, path);
+    const searchSource = new SearchSource(
+      await createContext(config.projectConfig, {
+        maxWorkers: 1,
+        watchman: false,
+        watch: false,
+        console: NO_WARNINGS_CONSOLE,
+      })
+    );
+
+    const results = await searchSource.getTestPaths(config.globalConfig, undefined, undefined);
+
+    return {
+      path,
+      testPaths: new Set(results.tests.map((t) => t.path)),
+    };
+  });
+}