refactor: share sampled entry summary formatting

src/shared/string-sample.test.ts

@@ -0,0 +1,21 @@
+import { describe, expect, it } from "vitest";
+import { summarizeStringEntries } from "./string-sample.js";
+
+describe("summarizeStringEntries", () => {
+  it("returns emptyText for empty lists", () => {
+    expect(summarizeStringEntries({ entries: [], emptyText: "any" })).toBe("any");
+  });
+
+  it("joins short lists without a suffix", () => {
+    expect(summarizeStringEntries({ entries: ["a", "b"], limit: 4 })).toBe("a, b");
+  });
+
+  it("adds a remainder suffix when truncating", () => {
+    expect(
+      summarizeStringEntries({
+        entries: ["a", "b", "c", "d", "e"],
+        limit: 4,
+      }),
+    ).toBe("a, b, c, d (+1)");
+  });
+});