[codex] test: lift utility coverage above TaskBounty target

package.json

@@ -5,7 +5,7 @@
   "type": "module",
   "scripts": {
     "test": "vitest run",
-    "test:coverage": "vitest run --coverage --coverage.reporter=text-summary --coverage.include='src/**/*.ts' --coverage.exclude='src/**/*.test.ts'"
+    "test:coverage": "vitest run --coverage --coverage.reporter=text-summary --coverage.include=src/**/*.ts --coverage.exclude=src/**/*.test.ts"
   },
   "devDependencies": {
     "@vitest/coverage-v8": "^2.0.0",

src/arrays.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, it } from "vitest";
+import { chunk, dedupe, groupBy } from "./arrays";
+
+describe("chunk", () => {
+  it("splits arrays into fixed-size groups and keeps a shorter tail", () => {
+    expect(chunk([1, 2, 3, 4, 5], 2)).toEqual([[1, 2], [3, 4], [5]]);
+  });
+
+  it("returns an empty list for non-positive chunk sizes", () => {
+    expect(chunk([1, 2, 3], 0)).toEqual([]);
+    expect(chunk([1, 2, 3], -1)).toEqual([]);
+  });
+});
+
+describe("dedupe", () => {
+  it("preserves first-seen order while removing duplicates", () => {
+    expect(dedupe(["a", "b", "a", "c", "b"])).toEqual(["a", "b", "c"]);
+  });
+});
+
+describe("groupBy", () => {
+  it("groups items by string or numeric keys", () => {
+    const grouped = groupBy(
+      [
+        { kind: "fruit", name: "apple" },
+        { kind: "veg", name: "carrot" },
+        { kind: "fruit", name: "pear" },
+      ],
+      (item) => item.kind,
+    );
+
+    expect(grouped).toEqual({
+      fruit: [
+        { kind: "fruit", name: "apple" },
+        { kind: "fruit", name: "pear" },
+      ],
+      veg: [{ kind: "veg", name: "carrot" }],
+    });
+  });
+});

src/dates.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it } from "vitest";
+import { addDays, daysBetween, isWeekend, startOfDayUTC } from "./dates";
+
+describe("daysBetween", () => {
+  it("returns an absolute rounded day count", () => {
+    const morning = new Date("2026-05-01T06:00:00Z");
+    const nextEvening = new Date("2026-05-02T20:00:00Z");
+
+    expect(daysBetween(morning, nextEvening)).toBe(2);
+    expect(daysBetween(nextEvening, morning)).toBe(2);
+  });
+});
+
+describe("isWeekend", () => {
+  it("identifies Saturdays and Sundays as weekends", () => {
+    expect(isWeekend(new Date("2026-05-23T12:00:00Z"))).toBe(true);
+    expect(isWeekend(new Date("2026-05-24T12:00:00Z"))).toBe(true);
+  });
+
+  it("treats weekdays as non-weekends", () => {
+    expect(isWeekend(new Date("2026-05-25T12:00:00Z"))).toBe(false);
+  });
+});
+
+describe("addDays", () => {
+  it("returns a new date shifted by the requested number of days", () => {
+    const input = new Date("2026-05-01T10:30:00Z");
+    const shifted = addDays(input, 5);
+
+    expect(shifted.toISOString()).toBe("2026-05-06T10:30:00.000Z");
+    expect(input.toISOString()).toBe("2026-05-01T10:30:00.000Z");
+  });
+});
+
+describe("startOfDayUTC", () => {
+  it("normalizes a date to midnight in UTC", () => {
+    expect(startOfDayUTC(new Date("2026-05-01T23:59:59Z")).toISOString()).toBe(
+      "2026-05-01T00:00:00.000Z",
+    );
+  });
+});

src/money.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it } from "vitest";
+import { formatCents, netPayoutCents, platformFeeCents, splitEvenly } from "./money";
+
+describe("formatCents", () => {
+  it("formats USD with a dollar prefix", () => {
+    expect(formatCents(12345)).toBe("$123.45");
+  });
+
+  it("formats EUR with the library's euro prefix", () => {
+    expect(formatCents(12345, "EUR")).toBe("€123.45");
+  });
+
+  it("falls back to an ISO-like currency prefix for other currencies", () => {
+    expect(formatCents(12345, "GBP")).toBe("GBP 123.45");
+  });
+});
+
+describe("platformFeeCents", () => {
+  it("rounds basis-point fees to whole cents", () => {
+    expect(platformFeeCents(999, 250)).toBe(25);
+  });
+
+  it("returns zero for non-positive gross amounts or fee rates", () => {
+    expect(platformFeeCents(0, 250)).toBe(0);
+    expect(platformFeeCents(1000, 0)).toBe(0);
+  });
+});
+
+describe("netPayoutCents", () => {
+  it("subtracts the platform fee from the gross amount", () => {
+    expect(netPayoutCents(1000, 250)).toBe(975);
+  });
+});
+
+describe("splitEvenly", () => {
+  it("splits cents evenly and distributes the remainder from the front", () => {
+    expect(splitEvenly(10, 3)).toEqual([4, 3, 3]);
+  });
+
+  it("returns no shares for non-positive recipient counts", () => {
+    expect(splitEvenly(10, 0)).toEqual([]);
+  });
+});

src/strings.test.ts

@@ -1,7 +1,40 @@
 import { describe, it, expect } from "vitest";
-import { slugify } from "./strings";
+import { escapeHtml, slugify, titleCase, truncate } from "./strings";
 describe("slugify", () => {
   it("lowercases and dashifies basic input", () => {
     expect(slugify("Hello World")).toBe("hello-world");
   });
+
+  it("removes punctuation and collapses duplicate dashes", () => {
+    expect(slugify("  Hello, --- Tiny Utils!!  ")).toBe("hello-tiny-utils");
+  });
+});
+
+describe("truncate", () => {
+  it("keeps short strings unchanged", () => {
+    expect(truncate("short", 10)).toBe("short");
+  });
+
+  it("truncates longer strings with the default suffix", () => {
+    expect(truncate("abcdef", 5)).toBe("abcd…");
+  });
+
+  it("supports empty results and custom suffixes", () => {
+    expect(truncate("abcdef", 0)).toBe("");
+    expect(truncate("abcdef", 4, "..")).toBe("ab..");
+  });
+});
+
+describe("titleCase", () => {
+  it("capitalizes words and lowercases the remainder", () => {
+    expect(titleCase("hELLO tiny UTILS")).toBe("Hello Tiny Utils");
+  });
+});
+
+describe("escapeHtml", () => {
+  it("escapes characters that are significant in HTML", () => {
+    expect(escapeHtml(`Tom & "Jerry" <cat>'s>`)).toBe(
+      "Tom &amp; &quot;Jerry&quot; &lt;cat&gt;&#39;s&gt;",
+    );
+  });
 });