Fix/4737/timeout error message for http

lib/adapters/http.js

@@ -420,9 +420,13 @@ module.exports = function httpAdapter(config) {
       // ClientRequest.setTimeout will be fired on the specify milliseconds, and can make sure that abort() will be fired after connect.
       req.setTimeout(timeout, function handleRequestTimeout() {
         req.abort();
+        var timeoutErrorMessage = config.timeout ? 'timeout of ' + config.timeout + 'ms exceeded' : 'timeout exceeded';
         var transitional = config.transitional || transitionalDefaults;
+        if (config.timeoutErrorMessage) {
+          timeoutErrorMessage = config.timeoutErrorMessage;
+        }
         reject(new AxiosError(
-          'timeout of ' + timeout + 'ms exceeded',
+          timeoutErrorMessage,
           transitional.clarifyTimeoutError ? AxiosError.ETIMEDOUT : AxiosError.ECONNABORTED,
           config,
           req

test/unit/adapters/http.js

@@ -146,7 +146,7 @@ describe('supports http with nodejs', function () {
         assert.strictEqual(success, false, 'request should not succeed');
         assert.strictEqual(failure, true, 'request should fail');
         assert.strictEqual(error.code, 'ECONNABORTED');
-        assert.strictEqual(error.message, 'timeout of 250ms exceeded');
+        assert.strictEqual(error.message, 'oops, timeout');
         done();
       }, 300);
     });