src: Add proper error handling (#283)

Feature:

    Please see `doc/usage.md` for more information on error-handling.

test/telegram.js

@@ -27,6 +27,7 @@ const pollingPort = portindex++;
 const webHookPort = portindex++;
 const pollingPort2 = portindex++;
 const webHookPort2 = portindex++;
+const badTgServerPort = portindex++;
 const staticUrl = `http://127.0.0.1:${staticPort}`;
 const key = `${__dirname}/../examples/key.pem`;
 const cert = `${__dirname}/../examples/crt.pem`;
@@ -39,6 +40,8 @@ before(function beforeAll() {
   return utils.startMockServer(pollingPort)
     .then(() => {
       return utils.startMockServer(pollingPort2);
+    }).then(() => {
+      return utils.startMockServer(badTgServerPort, { bad: true });
     });
 });
 
@@ -125,17 +128,33 @@ describe('TelegramBot', function telegramSuite() {
         return done();
       });
     });
+    it('(polling) emits "polling_error" if error occurs during polling', function test(done) {
+      const myBot = new TelegramBot(12345, { polling: true });
+      myBot.once('polling_error', (error) => {
+        assert.ok(error);
+        assert.equal(error.code, 'ETELEGRAM');
+        return myBot.stopPolling().then(() => { done(); }).catch(done);
+      });
+    });
     it('(webhook) emits "message" on receiving message', function test(done) {
       botWebHook.once('message', () => {
         return done();
       });
       utils.sendWebHookMessage(webHookPort2, TOKEN);
     });
+    it('(webhook) emits "webhook_error" if could not parse webhook request body', function test(done) {
+      botWebHook.once('webhook_error', (error) => {
+        assert.ok(error);
+        assert.equal(error.code, 'EPARSE');
+        return done();
+      });
+      utils.sendWebHookMessage(webHookPort2, TOKEN, { update: 'unparseable!', json: false });
+    });
   });
 
   describe('WebHook', function webHookSuite() {
     it('returns 200 OK for health endpoint', function test(done) {
-      utils.sendWebHookRequest(webHookPort2, '/healthz', { json: false }).then(resp => {
+      utils.sendWebHookRequest(webHookPort2, '/healthz').then(resp => {
         assert.equal(resp, 'OK');
         return done();
       });
@@ -186,6 +205,58 @@ describe('TelegramBot', function telegramSuite() {
     });
   });
 
+  describe('errors', function errorsSuite() {
+    const botParse = new TelegramBot('useless-token', {
+      baseApiUrl: `http://localhost:${badTgServerPort}`,
+    });
+    it('FatalError is thrown if token is missing', function test() {
+      const myBot = new TelegramBot(null);
+      return myBot.sendMessage(USERID, 'text').catch(error => {
+        // FIX: assert.ok(error instanceof TelegramBot.errors.FatalError);
+        assert.equal(error.code, 'EFATAL');
+        assert.ok(error.message.indexOf('not provided') > -1);
+      });
+    });
+    it('FatalError is thrown if file-type of Buffer could not be determined', function test() {
+      let buffer;
+      try {
+        buffer = Buffer.from('12345');
+      } catch (ex) {
+        buffer = new Buffer('12345');
+      }
+      return bot.sendPhoto(USERID, buffer).catch(error => {
+        // FIX: assert.ok(error instanceof TelegramBot.errors.FatalError);
+        assert.equal(error.code, 'EFATAL');
+        assert.ok(error.message.indexOf('Unsupported') > -1);
+      });
+    });
+    it('FatalError is thrown on network error', function test() {
+      const myBot = new TelegramBot('useless-token', {
+        baseApiUrl: 'http://localhost:23', // are we sure this port is not bound to?
+      });
+      return myBot.getMe().catch(error => {
+        // FIX: assert.ok(error instanceof TelegramBot.errors.FatalError);
+        assert.equal(error.code, 'EFATAL');
+      });
+    });
+    it('ParseError is thrown if response body could not be parsed', function test() {
+      botParse.sendMessage(USERID, 'text').catch(error => {
+        // FIX: assert.ok(error instanceof TelegramBot.errors.ParseError);
+        assert.equal(error.code, 'EPARSE');
+        assert.ok(typeof error.response === 'object');
+        assert.ok(typeof error.response.body === 'string');
+      });
+    });
+    it('TelegramError is thrown if error is from Telegram', function test() {
+      return bot.sendMessage('404', 'text').catch(error => {
+        // FIX: assert.ok(error instanceof TelegramBot.errors.TelegramError);
+        assert.equal(error.code, 'ETELEGRAM');
+        assert.ok(typeof error.response === 'object');
+        assert.ok(typeof error.response.body === 'object');
+      });
+    });
+  });
+
   describe('#startPolling', function initPollingSuite() {
     it('initiates polling', function test() {
       return testbot.startPolling().then(() => {
@@ -195,6 +266,8 @@ describe('TelegramBot', function telegramSuite() {
     it('returns error if using webhook', function test() {
       return botWebHook.startPolling().catch((err) => {
         // TODO: check for error in a better way
+        // FIX: assert.ok(err instanceof TelegramBot.errors.FatalError);
+        assert.equal(err.code, 'EFATAL');
         assert.ok(err.message.indexOf('mutually exclusive') !== -1);
       });
     });
@@ -235,6 +308,8 @@ describe('TelegramBot', function telegramSuite() {
     it('returns error if using polling', function test() {
       return botPolling.openWebHook().catch((err) => {
         // TODO: check for error in a better way
+        // FIX: assert.ok(err instanceof TelegramBot.errors.FatalError);
+        assert.equal(err.code, 'EFATAL');
         assert.ok(err.message.indexOf('mutually exclusive') !== -1);
       });
     });
@@ -1020,7 +1095,7 @@ describe('TelegramBot', function telegramSuite() {
       const photo = `${__dirname}/data/photo.gif`;
       return tgbot.sendPhoto(USERID, photo).catch(err => {
         // TODO: check for error in a better way
-        assert.ok(err.response.body.indexOf('Bad Request') !== -1);
+        assert.ok(err.response.body.description.indexOf('Bad Request') !== -1);
       });
     });
     it('should allow stream.path that can not be parsed', function test() {