Add tests to lift coverage above 80%

src/arrays.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, it } from "vitest";
+import { chunk, dedupe, groupBy } from "./arrays";
+
+describe("chunk", () => {
+  it("splits arrays into fixed-size groups and keeps the remainder", () => {
+    expect(chunk([1, 2, 3, 4, 5], 2)).toEqual([[1, 2], [3, 4], [5]]);
+  });
+
+  it("returns an empty list for non-positive sizes", () => {
+    expect(chunk([1, 2, 3], 0)).toEqual([]);
+    expect(chunk([1, 2, 3], -1)).toEqual([]);
+  });
+});
+
+describe("dedupe", () => {
+  it("keeps first-seen values and removes later duplicates", () => {
+    expect(dedupe(["a", "b", "a", "c", "b"])).toEqual(["a", "b", "c"]);
+  });
+});
+
+describe("groupBy", () => {
+  it("groups values by the key returned from the callback", () => {
+    expect(groupBy(["ant", "bat", "ape"], (value) => value[0])).toEqual({
+      a: ["ant", "ape"],
+      b: ["bat"]
+    });
+  });
+});

src/dates.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it } from "vitest";
+import { addDays, daysBetween, isWeekend, startOfDayUTC } from "./dates";
+
+describe("daysBetween", () => {
+  it("returns the rounded absolute day difference", () => {
+    const start = new Date("2026-05-01T12:00:00Z");
+    const end = new Date("2026-05-04T00:00:00Z");
+
+    expect(daysBetween(start, end)).toBe(3);
+    expect(daysBetween(end, start)).toBe(3);
+  });
+});
+
+describe("isWeekend", () => {
+  it("detects Saturday and Sunday", () => {
+    expect(isWeekend(new Date("2026-05-23T12:00:00Z"))).toBe(true);
+    expect(isWeekend(new Date("2026-05-24T12:00:00Z"))).toBe(true);
+  });
+
+  it("returns false for weekdays", () => {
+    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 original = new Date("2026-05-27T10:30:00Z");
+    const shifted = addDays(original, 5);
+
+    expect(shifted.toISOString()).toBe("2026-06-01T10:30:00.000Z");
+    expect(original.toISOString()).toBe("2026-05-27T10:30:00.000Z");
+  });
+});
+
+describe("startOfDayUTC", () => {
+  it("normalizes a date to midnight UTC", () => {
+    expect(startOfDayUTC(new Date("2026-05-27T10:30:00Z")).toISOString()).toBe("2026-05-27T00:00:00.000Z");
+  });
+});

src/money.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, it } from "vitest";
+import { formatCents, netPayoutCents, platformFeeCents, splitEvenly } from "./money";
+
+describe("formatCents", () => {
+  it("formats USD and EUR with their symbols", () => {
+    expect(formatCents(1234)).toBe("$12.34");
+    expect(formatCents(1234, "EUR")).toBe("€12.34");
+  });
+
+  it("prefixes unknown currency codes", () => {
+    expect(formatCents(1234, "USDC")).toBe("USDC 12.34");
+  });
+});
+
+describe("platformFeeCents", () => {
+  it("rounds basis-point fees to the nearest cent", () => {
+    expect(platformFeeCents(12_345, 250)).toBe(309);
+  });
+
+  it("returns zero for non-positive gross amounts or fee rates", () => {
+    expect(platformFeeCents(0, 250)).toBe(0);
+    expect(platformFeeCents(12_345, 0)).toBe(0);
+  });
+});
+
+describe("netPayoutCents", () => {
+  it("subtracts the platform fee from the gross amount", () => {
+    expect(netPayoutCents(10_000, 250)).toBe(9_750);
+  });
+});
+
+describe("splitEvenly", () => {
+  it("distributes remainder cents to the earliest recipients", () => {
+    expect(splitEvenly(10, 3)).toEqual([4, 3, 3]);
+  });
+
+  it("returns an empty list for non-positive recipient counts", () => {
+    expect(splitEvenly(10, 0)).toEqual([]);
+  });
+});

src/strings.test.ts

@@ -1,7 +1,38 @@
 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, trims edge dashes, and collapses repeated dashes", () => {
+    expect(slugify("  Hello,   Tiny--Utils!!!  ")).toBe("hello-tiny-utils");
+  });
+});
+
+describe("truncate", () => {
+  it("returns the original string when it fits within the maximum", () => {
+    expect(truncate("short", 10)).toBe("short");
+  });
+
+  it("shortens long strings and appends the suffix", () => {
+    expect(truncate("abcdef", 4)).toBe("abc…");
+  });
+
+  it("returns an empty string for non-positive maximum lengths", () => {
+    expect(truncate("abcdef", 0)).toBe("");
+  });
+});
+
+describe("titleCase", () => {
+  it("capitalizes each word and lowercases the rest", () => {
+    expect(titleCase("hELLO tiny UTILS")).toBe("Hello Tiny Utils");
+  });
+});
+
+describe("escapeHtml", () => {
+  it("escapes HTML-sensitive characters", () => {
+    expect(escapeHtml(`<a href="x">Tom & 'Jerry'</a>`)).toBe("&lt;a href=&quot;x&quot;&gt;Tom &amp; &#39;Jerry&#39;&lt;/a&gt;");
+  });
 });