chore: import upstream snapshot with attribution

tests/unit/select-impacted-tests.test.ts

@@ -0,0 +1,62 @@
+/**
+ * tests/unit/select-impacted-tests.test.ts
+ *
+ * TIA (Test Impact Analysis) selector — given a PR's changed files plus the
+ * import-graph impact map, pick the impacted unit tests with a run-all
+ * fail-safe. The `__RUN_ALL__` sentinel and `selectImpacted({changed, map})`
+ * signature are load-bearing — CI wiring depends on them.
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { selectImpacted } from "../../scripts/quality/select-impacted-tests.mjs";
+
+const MAP = {
+  sources: {
+    "open-sse/services/combo.ts": ["tests/unit/combo-routing-engine.test.ts"],
+    "src/sse/services/auth.ts": ["tests/unit/sse-auth.test.ts"],
+  },
+};
+
+test("mapped source → its impacted test(s)", () => {
+  const sel = selectImpacted({ changed: ["open-sse/services/combo.ts"], map: MAP });
+  assert.deepEqual(sel, ["tests/unit/combo-routing-engine.test.ts"]);
+});
+
+test("changed test file → itself (always run a changed test)", () => {
+  const sel = selectImpacted({ changed: ["tests/unit/sse-auth.test.ts"], map: MAP });
+  assert.deepEqual(sel, ["tests/unit/sse-auth.test.ts"]);
+});
+
+test("hub file (setupPolyfill) → run all (fail-safe)", () => {
+  const sel = selectImpacted({ changed: ["open-sse/utils/setupPolyfill.ts"], map: MAP });
+  assert.deepEqual(sel, ["__RUN_ALL__"]);
+});
+
+test("unmapped source file → run all (fail-safe)", () => {
+  const sel = selectImpacted({ changed: ["open-sse/brand-new-file.ts"], map: MAP });
+  assert.deepEqual(sel, ["__RUN_ALL__"]);
+});
+
+// The TIA step runs selected files via `node --test`, so it must only ever select
+// node:test unit files (the `test:unit` glob). vitest/.tsx/e2e/integration changes
+// must NOT be selected — running them under node:test was the 99-false-failure bug.
+test("changed vitest UI test (.test.tsx) → NOT selected", () => {
+  const sel = selectImpacted({ changed: ["tests/unit/free-pool-tab.test.tsx"], map: MAP });
+  assert.deepEqual(sel, []);
+});
+
+test("changed e2e test → NOT selected (not a node:test unit file)", () => {
+  const sel = selectImpacted({ changed: ["tests/e2e/system-failover.test.ts"], map: MAP });
+  assert.deepEqual(sel, []);
+});
+
+test("changed vitest file in uncurated tests/unit/autoCombo → NOT selected", () => {
+  const sel = selectImpacted({ changed: ["tests/unit/autoCombo/tieredRotation.test.ts"], map: MAP });
+  assert.deepEqual(sel, []);
+});
+
+test("changed unit test in a curated subdir → run itself", () => {
+  const sel = selectImpacted({ changed: ["tests/unit/db/migration.test.ts"], map: MAP });
+  assert.deepEqual(sel, ["tests/unit/db/migration.test.ts"]);
+});