diff --git a/src/index.js b/src/index.js
index 3936205..895ddbd 100644
--- a/src/index.js
+++ b/src/index.js
@@ -73,7 +73,7 @@ let checkTags = (listTags) => {
   return isValid;
 };
 
-exports.findMenu = (opts = DEFAULT_MENUS_OPTIONS) => {
+let findMenu = (opts = DEFAULT_MENUS_OPTIONS) => {
   opts.language = opts.language || DEFAULT_MENUS_OPTIONS.language;
   opts.partOfDay = opts.partOfDay || DEFAULT_MENUS_OPTIONS.partOfDay;
 
@@ -97,7 +97,22 @@ exports.findMenu = (opts = DEFAULT_MENUS_OPTIONS) => {
     opts.tags = listTags.join(',');
   }
 
-  const url = buildMenuUrl(opts);
+  return getMenu(opts);
+};
+
+let getMenu = async function (opts) {
+  if (opts.restoId && isNaN(opts.restoId)) {
+    return Promise.reject(new TypeError('Not a valid restoId'));
+  }
+  let resto = await findResto(opts.restoId);
+  if (resto.length > 0) {
+    const url = buildMenuUrl(opts);
+    return promGetMenu(url);
+  }
+  return Promise.reject(new TypeError('Not a valid restoId'));
+};
+
+let promGetMenu = (url) => {
   return new Promise((resolve, reject) => {
     got(url).then((response) => {
       let jsonString = escapeTab(response.body);
@@ -107,7 +122,7 @@ exports.findMenu = (opts = DEFAULT_MENUS_OPTIONS) => {
   });
 };
 
-exports.findResto = (id) => {
+let findResto = (id) => {
   const url = buildRestoUrl(id);
   return new Promise((resolve, reject) => {
     got(url).then((response) => {
@@ -133,3 +148,6 @@ exports.translateTags = (strTags) => {
   }
   return translatedList.join(',');
 };
+
+exports.findMenu = findMenu;
+exports.findResto = findResto;
diff --git a/test/test-findMenu.js b/test/test-findMenu.js
index 6bd22d7..205e53e 100644
--- a/test/test-findMenu.js
+++ b/test/test-findMenu.js
@@ -11,21 +11,21 @@ const epflMenuApi = require('../src/index.js');
 describe('epfl-menu-api findMenu', function () {
   this.timeout(10000);
 
-  it('should throw an exception with an invalid date', () => {
+  it('should throw an exception with the date "30/02/2019"', () => {
     return epflMenuApi.findMenu({
       date: '30/02/2019'
     }).then(() => {
     }).catch((err) => err.message.should.equal('Not a valid date'));
   });
 
-  it('should throw an exception with a language not supported', () => {
+  it('should throw an exception with the language "de"', () => {
     return epflMenuApi.findMenu({
       language: 'de'
     }).then(() => {
     }).catch((err) => err.message.should.equal('Language not supported'));
   });
 
-  it('should throw an exception with a part of the day not supported', () => {
+  it('should throw an exception with the part of the day "morning"', () => {
     return epflMenuApi.findMenu({
       'partOfDay': 'morning'
     }).then(() => {
@@ -34,7 +34,7 @@ describe('epfl-menu-api findMenu', function () {
     );
   });
 
-  it('should throw an exception with a tag not supported', () => {
+  it('should throw an exception with the tag "Cheese"', () => {
     return epflMenuApi.findMenu({
       'tags': 'Cheese'
     }).then(() => {
@@ -43,7 +43,25 @@ describe('epfl-menu-api findMenu', function () {
     );
   });
 
-  it('should contains at least 5 menus', function () {
+  it('should throw an exception with the restoId "Cafétéria BC"', () => {
+    return epflMenuApi.findMenu({
+      'restoId': 'Cafétéria BC'
+    }).then(() => {
+    }).catch(
+      (err) => err.message.should.equal('Not a valid restoId')
+    );
+  });
+
+  it('should throw an exception with the restoId "999999"', () => {
+    return epflMenuApi.findMenu({
+      'restoId': 999999
+    }).then(() => {
+    }).catch(
+      (err) => err.message.should.equal('Not a valid restoId')
+    );
+  });
+
+  it('should contains at least 5 menus on 18/04/2019', function () {
     return epflMenuApi.findMenu({
       date: '18/04/2019',
       restoId: '22',