diff --git a/src/api.ts b/src/api.ts
index 86540db..c8da672 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -10,7 +10,13 @@ import {
   generateTranslationRequestData,
   generateSplitSentencesRequestData,
 } from './generators.js'
-import { API_URL, AUTO, SourceLanguage, TargetLanguage } from './settings.js'
+import {
+  API_URL,
+  AUTO,
+  FormalityTone,
+  SourceLanguage,
+  TargetLanguage,
+} from './settings.js'
 import { abbreviateLanguage } from './utils.js'
 
 const got = _got.extend({
@@ -72,7 +78,7 @@ export async function requestTranslation(
   sourceLanguage: SourceLanguage,
   identifier?: number,
   alternatives?: number,
-  formalityTone?: 'formal' | 'informal',
+  formalityTone?: FormalityTone,
 ) {
   const res = await splitSentences(text, sourceLanguage, identifier)
   const data = generateTranslationRequestData(
@@ -96,7 +102,7 @@ export async function translate(
   sourceLanguage?: SourceLanguage,
   identifier?: number,
   alternatives?: number,
-  formalityTone?: 'formal' | 'informal',
+  formalityTone?: FormalityTone,
 ): Promise<undefined>
 export async function translate(
   text: string,
@@ -104,7 +110,7 @@ export async function translate(
   sourceLanguage?: SourceLanguage,
   identifier?: number,
   alternatives?: number,
-  formalityTone?: 'formal' | 'informal',
+  formalityTone?: FormalityTone,
 ): Promise<string>
 export async function translate(
   text: string | null | undefined,
@@ -112,7 +118,7 @@ export async function translate(
   sourceLanguage?: SourceLanguage,
   identifier?: number,
   alternatives?: number,
-  formalityTone?: 'formal' | 'informal',
+  formalityTone?: FormalityTone,
 ): Promise<string | undefined>
 export async function translate(
   text: string | null | undefined,
@@ -120,7 +126,7 @@ export async function translate(
   sourceLanguage: SourceLanguage = AUTO,
   identifier?: number,
   alternatives?: number,
-  formalityTone?: 'formal' | 'informal',
+  formalityTone?: FormalityTone,
 ) {
   text = text?.trim()
   if (!text) {
diff --git a/src/generators.ts b/src/generators.ts
index 880f3c7..dbb8b20 100644
--- a/src/generators.ts
+++ b/src/generators.ts
@@ -2,7 +2,7 @@ import { generateId, generateTimestamp } from './hacks.js'
 import {
   AUTO,
   SUPPORTED_FORMALITY_TONES,
-  Formality,
+  FormalityTone,
   SourceLanguage,
   TargetLanguage,
 } from './settings.js'
@@ -45,13 +45,13 @@ export function generateJobs(sentences: string[], beams = 1) {
   }))
 }
 
-function generateCommonJobParams(formality?: Formality) {
+function generateCommonJobParams(formality?: FormalityTone) {
   if (!formality) {
     return {}
   }
 
   if (!SUPPORTED_FORMALITY_TONES.includes(formality)) {
-    throw new Error(`Formality tone ${formality} not supported.`)
+    throw new Error(`Formality tone \`${formality}\` not supported.`)
   }
 
   return { formality }
@@ -63,7 +63,7 @@ export function generateTranslationRequestData(
   sentences: string[],
   identifier = generateId(),
   alternatives = 1,
-  formality?: Formality,
+  formality?: FormalityTone,
 ) {
   return {
     jsonrpc: '2.0',
diff --git a/src/settings.ts b/src/settings.ts
index c5f8e59..194bd2b 100644
--- a/src/settings.ts
+++ b/src/settings.ts
@@ -43,4 +43,4 @@ export type SourceLanguage = TargetLanguage | 'auto'
 
 export const SUPPORTED_FORMALITY_TONES = ['formal', 'informal'] as const
 
-export type Formality = (typeof SUPPORTED_FORMALITY_TONES)[number]
+export type FormalityTone = (typeof SUPPORTED_FORMALITY_TONES)[number]
diff --git a/test/translation.spec.ts b/test/translation.spec.ts
index aff2746..d64426b 100644
--- a/test/translation.spec.ts
+++ b/test/translation.spec.ts
@@ -15,34 +15,34 @@ test('translate russian', async () => {
   const source_language = 'RU'
   const target_language = 'EN'
   const text = 'Я сошла с ума'
-  const expected_translation = "I'm out of my mind."
   const translation = await translate(text, target_language, source_language)
-  expect(translation).toEqual(expected_translation)
+  expect(translation).toMatchInlineSnapshot(`"I've lost my mind"`)
 })
 
 test('translate chinese', async () => {
   const source_language = 'ZH'
   const target_language = 'dutch'
   const text = '你好'
-  const expected_translation = 'Hallo'
   const translation = await translate(text, target_language, source_language)
-  expect(translation).toContain(expected_translation)
+  expect(translation).toMatchInlineSnapshot(`"Hoe gaat het met je?"`)
 })
 
 test('translate greek romanian', async () => {
   const source_language = 'gReEk'
   const target_language = 'rO'
   const text = 'Γεια σας'
-  const expected_translation = 'bună ziua'
   // @ts-expect-error -- only upper, lower or capitalize case languages are supported in TypeScript
   const translation = await translate(text, target_language, source_language)
-  expect((translation as string).toLowerCase()).toContain(expected_translation)
+  expect((translation as string).toLowerCase()).toMatchInlineSnapshot(
+    `"bună ziua."`,
+  )
 })
 
 test('translate sentence', async () => {
   const text = 'Up and down.'
-  const expected_translation = 'Op en neer.'
-  expect(await translate(text, 'NL', 'EN')).toBe(expected_translation)
+  expect(await translate(text, 'NL', 'EN')).toMatchInlineSnapshot(
+    `"Op en neer."`,
+  )
 })
 
 test('translate sentences', async () => {
@@ -103,5 +103,5 @@ test('invalid_formal_tone', () =>
     // @ts-expect-error
     translate('ABC', 'DE', 'EN', undefined, undefined, 'politically incorrect'),
   ).rejects.toThrowErrorMatchingInlineSnapshot(
-    `"Formality tone '{formality_tone}' not supported."`,
+    `[Error: Formality tone \`politically incorrect\` not supported.]`,
   ))
diff --git a/vitest.config.ts b/vitest.config.ts
index c5c143b..eb78e54 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -15,6 +15,7 @@ export default defineConfig({
   test: {
     coverage: {
       include: ['src'],
+      exclude: ['src/cli.ts'],
       provider: 'istanbul',
       reporter: ['lcov', 'json', 'text'],
     },