diff --git a/jest.config.json b/jest.config.json
index 7993dc4..224feb9 100644
--- a/jest.config.json
+++ b/jest.config.json
@@ -7,13 +7,5 @@
 	"extensionsToTreatAsEsm": [".ts"],
 	"moduleNameMapper": {
 		"^(\\.{1,2}/.*)\\.js$": "$1"
-	},
-	"transform": {
-		"^.+\\.[tj]sx?$": [
-			"ts-jest",
-			{
-				"useESM": true
-			}
-		]
 	}
 }
diff --git a/source/parser.ts b/source/parser.ts
index d0c6903..08785db 100644
--- a/source/parser.ts
+++ b/source/parser.ts
@@ -225,7 +225,7 @@ export const parseDraft7Header = (header: string): RateLimitInfo => {
  *
  * @param header {string} - The header's contents.
  */
-const parseResetHeader = (
+export const parseResetHeader = (
 	passedHeader: string | undefined,
 	options: Partial<ParserOptions>,
 ): Date | undefined => {
@@ -290,7 +290,7 @@ const parseResetMilliseconds = (header: string | number): Date =>
  * Find out what type of time is passed in the `RateLimit-Reset` header, and
  * parse it into a `Date`.
  */
-const parseResetAuto = (header: string): Date => {
+export const parseResetAuto = (header: string): Date => {
 	// If it has any letters, assume it's a date string.
 	if (/[a-z]/i.test(header)) return parseResetDate(header)
 
diff --git a/test/parser-test.ts b/test/parser-test.ts
index 172bad1..966703f 100644
--- a/test/parser-test.ts
+++ b/test/parser-test.ts
@@ -1,14 +1,15 @@
 // /test/parser-test.ts
 // Tests for the public API.
 
-import { describe, it, expect } from '@jest/globals'
+import { describe, test, expect } from '@jest/globals'
 import {
 	parseDraft7Header,
+	parseResetAuto,
 	getRateLimit,
 	getRateLimits,
 } from '../source/parser.js'
 
-const itif = (condition: boolean) => (condition ? it : it.skip)
+const testIf = (condition: boolean) => (condition ? test : test.skip)
 
 describe('input tests', () => {
 	const headers = {
@@ -24,15 +25,15 @@ describe('input tests', () => {
 	}
 
 	// NOTE: the `Header` and `Response` classes don't exist in node 16 or older.
-	itif(typeof Headers !== 'undefined')(
-		'should handle headers in a fetch-style headers object',
+	testIf(typeof Headers !== 'undefined')(
+		'fetch-style headers object parsing',
 		() => {
 			expect(getRateLimit(new Headers(headers))).toMatchObject(info)
 		},
 	)
 
-	itif(typeof Response !== 'undefined')(
-		'should handle headers in a node `ServerResponse` object',
+	testIf(typeof Response !== 'undefined')(
+		'fetch-style response object parsing',
 		() => {
 			const response = new Response('Hallo!', { headers })
 
@@ -40,13 +41,13 @@ describe('input tests', () => {
 		},
 	)
 
-	it('should handle headers in a node-style headers object', () => {
+	test('node-style headers object parsing', () => {
 		expect(getRateLimit(headers)).toMatchObject(info)
 	})
 })
 
 describe('api tests', () => {
-	it('should parse a header and return the parsed info', () => {
+	test('json header object parsing', () => {
 		const headers = {
 			'X-Rate-Limit-Limit': '500',
 			'X-Rate-Limit-Remaining': '499',
@@ -62,7 +63,7 @@ describe('api tests', () => {
 		expect(getRateLimit(headers)).toMatchObject(info)
 	})
 
-	it('should parse multiple headers and return all of them', () => {
+	test('multiple header parsing', () => {
 		const headers = {
 			'X-RateLimit-ClientLimit': '1000',
 			'X-RateLimit-ClientRemaining': '999',
@@ -93,7 +94,7 @@ describe('api tests', () => {
 		expect(getRateLimits(headers)).toMatchObject(infos)
 	})
 
-	it('should parse a combined header', () => {
+	test('combined header (draft 7) parsing', () => {
 		const header = 'limit=100, remaining=25, reset=5'
 		const info = {
 			limit: 100,
@@ -106,5 +107,30 @@ describe('api tests', () => {
 	})
 })
 
-// TODO: test options
-// TODO: test `parseResetAuto` with various formats
+describe('date tests', () => {
+	const thatDay = new Date('2023-05-16T18:12:13.000Z')
+
+	test('date string auto-detection', () => {
+		const dateString = 'Tuesday, May 16, 2023 11:42:13 PM GMT+05:30'
+
+		const parsedDate = parseResetAuto(dateString)
+		expect(parsedDate.getTime()).toBe(thatDay.getTime())
+	})
+
+	test('unix date auto-detection', () => {
+		const dateString = '1684260733'
+
+		const parsedDate = parseResetAuto(dateString)
+		expect(parsedDate.getTime()).toBe(thatDay.getTime())
+	})
+
+	test('delta seconds auto-detection', () => {
+		const now = new Date()
+		const then = new Date()
+		then.setSeconds(now.getSeconds() + 42)
+		const dateString = '42'
+
+		const parsedDate = parseResetAuto(dateString)
+		expect(parsedDate.getTime()).toBe(then.getTime())
+	})
+})