diff --git a/package.json b/package.json
index 6ee8279..59d1bbb 100644
--- a/package.json
+++ b/package.json
@@ -1,4 +1,6 @@
+
 {
+	"type": "module",
 	"scripts": {
 		"prettier-format-check": "prettier --check src/*",
 		"prettier-format-fix": "prettier --write src/*"
diff --git a/src/lib/data.test.js b/src/lib/data.test.js
new file mode 100644
index 0000000..7862f3d
--- /dev/null
+++ b/src/lib/data.test.js
@@ -0,0 +1,74 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import {
+	fetchJurisdictionsData,
+	fetchReporterData,
+	fetchVolumesData,
+	fetchCasesList,
+	fetchCaselawBody,
+	fetchCaseMetadata,
+	getBreadcrumbLinks,
+} from "./data.js";
+
+global.window = { BUCKET_ROOT: "https://cap-redacted-demo.lil.tools" };
+
+test("fetchJurisdictionsData fetches jurisdictions ", async (t) => {
+	await fetchJurisdictionsData((data) => {
+		assert.ok(data instanceof Object);
+		assert.ok(Object.keys(data).length > 3);
+		assert.ok(Object.keys(data).includes("Arkansas"));
+	});
+});
+
+test("fetchReporterData can fetch metadata for a reporter", async (t) => {
+	await fetchReporterData("ark", (data) => {
+		assert.ok(data instanceof Object);
+		assert.strictEqual(data.slug, "ark");
+	});
+});
+
+test("fetchVolumeData can fetch a list of volumes", async (t) => {
+	await fetchVolumesData("ark", (data) => {
+		assert.ok(data instanceof Array);
+		assert.ok(data.length > 100);
+	});
+});
+
+test("fetchCasesList can load a list of cases", async (t) => {
+	await fetchCasesList("ark", "1", (data) => {
+		assert.ok(data instanceof Array);
+		assert.ok(data.length > 50);
+	});
+});
+
+test("fetchCaselawBody can load a case html file", async (t) => {
+	await fetchCaselawBody("ark", "1", "0011-01", (data) => {
+		// literal strings arent instances of String, so we have to use typeof
+		assert.strictEqual(typeof data, "string");
+		assert.match(data, /<section/);
+	});
+});
+
+test("fetchCaseMetadata can load a case metadata file", async (t) => {
+	await fetchCaseMetadata("ark", "1", "0011-01", (data) => {
+		assert.ok(data instanceof Object);
+		assert.strictEqual(data.name, "Goings against Mills");
+	});
+});
+
+test("getBreadcrumbLinks", async (t) => {
+	const reporterData = {
+		slug: "ark",
+		short_name: "Arkansas",
+	};
+	const volume = "1";
+	const expected = [
+		{
+			url: "/caselaw/?reporter=ark",
+			name: "Reporter Arkansas",
+		},
+		{ url: "/caselaw/?reporter=ark&volume=1", name: "Volume 1" },
+	];
+	const links = getBreadcrumbLinks(reporterData, volume);
+	assert.deepStrictEqual(links, expected);
+});
diff --git a/src/lib/fetchOr404.test.js b/src/lib/fetchOr404.test.js
new file mode 100644
index 0000000..e30ed6e
--- /dev/null
+++ b/src/lib/fetchOr404.test.js
@@ -0,0 +1,38 @@
+import { test, before } from "node:test";
+import assert from "node:assert/strict";
+
+import { fetchOr404 } from "./fetchOr404.js";
+
+let newLocation = "";
+
+const window = {
+	location: {
+		replace: function (url) {
+			newLocation = url;
+		},
+		search: "foo",
+	},
+};
+
+global.window = window;
+global.location = window.location;
+
+before(() => (newLocation = ""));
+
+test("fetchOr404 works when the fetches work.", async (t) => {
+	const fetches = [
+		() => Promise.resolve("first fetch"),
+		() => Promise.resolve("second fetch"),
+	];
+	await fetchOr404(...fetches);
+	assert.strictEqual(newLocation, "");
+});
+
+test("fetchOr404 redirects when a fetch fails.", async (t) => {
+	const fetches = [
+		() => Promise.resolve("first fetch"),
+		() => Promise.reject("second fetch"),
+	];
+	await fetchOr404(...fetches);
+	assert.equal(newLocation, "./not-found/foo");
+});
diff --git a/src/lib/isEmpty.js b/src/lib/isEmpty.js
index 1a172c0..1e7398d 100644
--- a/src/lib/isEmpty.js
+++ b/src/lib/isEmpty.js
@@ -1,12 +1,12 @@
 export const isEmpty = (obj) => {
 	if (obj === null || obj === undefined) {
-		return True;
+		return true;
 	} else if (Array.isArray(obj) || typeof obj === "string") {
 		return obj.length === 0;
 	} else if (
 		["boolean", "number", "bigint", "symbol", "function"].includes(typeof obj)
 	) {
-		throw new Error(f`Unsuported type: ${typeof obj}`);
+		throw new Error(`Unsuported type: ${typeof obj}`);
 	} else {
 		return Object.keys(obj).length === 0;
 	}
diff --git a/src/lib/isEmpty.test.js b/src/lib/isEmpty.test.js
new file mode 100644
index 0000000..0f448ac
--- /dev/null
+++ b/src/lib/isEmpty.test.js
@@ -0,0 +1,81 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+import { isEmpty } from "./isEmpty.js";
+
+test("isEmpty returns true for empty objects", (t) => {
+	const emptyObj = {};
+	assert(isEmpty(emptyObj));
+});
+
+test("isEmpty returns true for empty arrays", (t) => {
+	const emptyArray = [];
+	assert.ok(isEmpty(emptyArray));
+});
+
+test("isEmpty returns true for empty strings", (t) => {
+	const emptyString = "";
+	assert.ok(isEmpty(emptyString));
+});
+
+test("isEmpty returns false for non-empty objects", (t) => {
+	const nonEmptyObj = { a: 1 };
+	assert.ok(!isEmpty(nonEmptyObj));
+});
+
+test("isEmpty returns false for non-empty arrays", (t) => {
+	const nonEmptyArray = [1];
+	assert.ok(!isEmpty(nonEmptyArray));
+});
+
+test("isEmpty returns false for non-empty strings", (t) => {
+	const nonEmptyString = "a";
+	assert.ok(!isEmpty(nonEmptyString));
+});
+
+test("isEmpty returns false for null", (t) => {
+	assert.ok(isEmpty(null));
+});
+
+test("isEmpty throws for unsupported types", (t) => {
+	assert.throws(
+		() => {
+			isEmpty(true);
+		},
+		{
+			message: "Unsuported type: boolean",
+		},
+	);
+	assert.throws(
+		() => {
+			isEmpty(1);
+		},
+		{
+			message: "Unsuported type: number",
+		},
+	);
+	assert.throws(
+		() => {
+			isEmpty(BigInt(9007199254740991));
+		},
+		{
+			message: "Unsuported type: bigint",
+		},
+	);
+	assert.throws(
+		() => {
+			isEmpty(Symbol("foo"));
+		},
+		{
+			message: "Unsuported type: symbol",
+		},
+	);
+	assert.throws(
+		() => {
+			isEmpty(() => {});
+		},
+		{
+			message: "Unsuported type: function",
+		},
+	);
+});
diff --git a/src/lib/slugify.test.js b/src/lib/slugify.test.js
new file mode 100644
index 0000000..11935c1
--- /dev/null
+++ b/src/lib/slugify.test.js
@@ -0,0 +1,16 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+import { slugify } from "./slugify.js";
+
+test("slugify replaces spaces with hyphens", (t) => {
+	const actual = slugify("hello world");
+	const expected = "hello-world";
+	assert.equal(actual, expected);
+});
+
+test("slugify replaces special characters with empty strings", (t) => {
+	const actual = slugify("hello!@#$%^&*()");
+	const expected = "hello";
+	assert.equal(actual, expected);
+});