;;; jsonrpc-tests.el --- tests for jsonrpc.el        -*- lexical-binding: t; -*-

;; Copyright (C) 2018-2021 Free Software Foundation, Inc.

;; Author: João Távora <joaotavora@gmail.com>
;; Keywords: tests

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; About "deferred" tests, `jsonrpc--test-client' has a flag that we
;; test in its `jsonrpc-connection-ready-p' API method.  It holds any
;; `jsonrpc-request's and `jsonrpc-async-request's explicitly passed
;; `:deferred'.  After clearing the flag, the held requests are
;; actually sent to the server in the next opportunity (when receiving
;; or sending something to the server).

;;; Code:

(require 'ert)
(require 'jsonrpc)
(require 'eieio)

(defclass jsonrpc--test-endpoint (jsonrpc-process-connection)
  ((scp :accessor jsonrpc--shutdown-complete-p)))

(defclass jsonrpc--test-client (jsonrpc--test-endpoint)
  ((hold-deferred :initform t :accessor jsonrpc--hold-deferred)))

(defun jsonrpc--call-with-emacsrpc-fixture (fn)
  "Do work for `jsonrpc--with-emacsrpc-fixture'.  Call FN."
  (let* (listen-server endpoint)
    (unwind-protect
        (progn
          (setq listen-server
                (make-network-process
                 :name "Emacs RPC server" :server t :host "localhost"
                 :service (if (version<= emacs-version "26.1")
                              44444
                            ;; 26.1 can automatically find ports if
                            ;; one passes 0 here.
                            0)
                 :log (lambda (listen-server client _message)
                        (push
                         (make-instance
                          'jsonrpc--test-endpoint
                          :name (process-name client)
                          :process client
                          :request-dispatcher
                          (lambda (_endpoint method params)
                            (unless (memq method '(+ - * / vconcat append
                                                     sit-for ignore))
                              (signal 'jsonrpc-error
                                      '((jsonrpc-error-message
                                         . "Sorry, this isn't allowed")
                                        (jsonrpc-error-code . -32601))))
                            (apply method (append params nil)))
                          :on-shutdown
                          (lambda (conn)
                            (setf (jsonrpc--shutdown-complete-p conn) t)))
                         (process-get listen-server 'handlers)))))
          (setq endpoint
                (make-instance
                 'jsonrpc--test-client
                 "Emacs RPC client"
                 :process
                 (open-network-stream "JSONRPC test tcp endpoint"
                                      nil "localhost"
                                      (process-contact listen-server
                                                       :service))
                 :on-shutdown
                 (lambda (conn)
                   (setf (jsonrpc--shutdown-complete-p conn) t))))
          (funcall fn endpoint))
      (unwind-protect
          (when endpoint
            (kill-buffer (jsonrpc--events-buffer endpoint))
            (jsonrpc-shutdown endpoint))
        (when listen-server
          (cl-loop do (delete-process listen-server)
                   while (progn (accept-process-output nil 0.1)
                                (process-live-p listen-server))
                   do (jsonrpc--message
                       "test listen-server is still running, waiting"))
          (cl-loop for handler in (process-get listen-server 'handlers)
                   do (ignore-errors (jsonrpc-shutdown handler)))
          (mapc #'kill-buffer
                (mapcar #'jsonrpc--events-buffer
                        (process-get listen-server 'handlers))))))))

(cl-defmacro jsonrpc--with-emacsrpc-fixture ((endpoint-sym) &body body)
  `(jsonrpc--call-with-emacsrpc-fixture (lambda (,endpoint-sym) ,@body)))

(ert-deftest returns-3 ()
  "A basic test for adding two numbers in our test RPC."
  (jsonrpc--with-emacsrpc-fixture (conn)
    (should (= 3 (jsonrpc-request conn '+ [1 2])))))

(ert-deftest errors-with--32601 ()
  "Errors with -32601"
  (jsonrpc--with-emacsrpc-fixture (conn)
    (condition-case err
        (progn
          (jsonrpc-request conn 'delete-directory "~/tmp")
          (ert-fail "A `jsonrpc-error' should have been signaled!"))
      (jsonrpc-error
       (should (= -32601 (cdr (assoc 'jsonrpc-error-code (cdr err)))))))))

(ert-deftest signals-an--32603-JSONRPC-error ()
  "Signals an -32603 JSONRPC error."
  (jsonrpc--with-emacsrpc-fixture (conn)
    (condition-case err
        (progn
          (jsonrpc-request conn '+ ["a" 2])
          (ert-fail "A `jsonrpc-error' should have been signaled!"))
      (jsonrpc-error
       (should (= -32603 (cdr (assoc 'jsonrpc-error-code (cdr err)))))))))

(ert-deftest times-out ()
  "Request for 3-sec sit-for with 1-sec timeout times out."
  (jsonrpc--with-emacsrpc-fixture (conn)
    (should-error
     (jsonrpc-request conn 'sit-for [3] :timeout 1))))

(ert-deftest doesnt-time-out ()
  :tags '(:expensive-test)
  "Request for 1-sec sit-for with 2-sec timeout succeeds."
  (jsonrpc--with-emacsrpc-fixture (conn)
    (jsonrpc-request conn 'sit-for [1] :timeout 2)))

(ert-deftest stretching-it-but-works ()
  "Vector of numbers or vector of vector of numbers are serialized."
  (jsonrpc--with-emacsrpc-fixture (conn)
    ;; (vconcat [1 2 3] [3 4 5]) => [1 2 3 3 4 5] which can be
    ;; serialized.
    (should (equal
             [1 2 3 3 4 5]
             (jsonrpc-request conn 'vconcat [[1 2 3] [3 4 5]])))))

(ert-deftest json-el-cant-serialize-this ()
  "Can't serialize a response that is half-vector/half-list."
  (jsonrpc--with-emacsrpc-fixture (conn)
                                  (should-error
                                   ;; (append [1 2 3] [3 4 5]) => (1 2 3 . [3 4 5]), which can't be
                                   ;; serialized
                                   (jsonrpc-request conn 'append [[1 2 3] [3 4 5]]))))

(cl-defmethod jsonrpc-connection-ready-p
  ((conn jsonrpc--test-client) what)
  (and (cl-call-next-method)
       (or (not (string-match "deferred" what))
           (not (jsonrpc--hold-deferred conn)))))

(ert-deftest deferred-action-toolate ()
  :tags '(:expensive-test)
  "Deferred request fails because no one clears the flag."
  (jsonrpc--with-emacsrpc-fixture (conn)
    (should-error
     (jsonrpc-request conn '+ [1 2]
                      :deferred "deferred-testing" :timeout 0.5)
     :type 'jsonrpc-error)
    (should
     (= 3 (jsonrpc-request conn '+ [1 2]
                           :timeout 0.5)))))

(ert-deftest deferred-action-intime ()
  :tags '(:expensive-test)
  "Deferred request barely makes it after event clears a flag."
  ;; Send an async request, which returns immediately. However the
  ;; success fun which sets the flag only runs after some time.
  (jsonrpc--with-emacsrpc-fixture (conn)
    (jsonrpc-async-request conn
                           'sit-for [0.5]
                           :success-fn
                           (lambda (_result)
                             (setf (jsonrpc--hold-deferred conn) nil)))
    ;; Now wait for an answer to this request, which should be sent as
    ;; soon as the previous one is answered.
    (should
     (= 3 (jsonrpc-request conn '+ [1 2]
                           :deferred "deferred"
                           :timeout 1)))))

(ert-deftest deferred-action-complex-tests ()
  :tags '(:expensive-test)
  "Test a more complex situation with deferred requests."
  (jsonrpc--with-emacsrpc-fixture (conn)
    (let (n-deferred-1
          n-deferred-2
          second-deferred-went-through-p)
      ;; This returns immediately
      (jsonrpc-async-request
       conn
       'sit-for [0.1]
       :success-fn
       (lambda (_result)
         ;; this only gets runs after the "first deferred" is stashed.
         (setq n-deferred-1
               (hash-table-count (jsonrpc--deferred-actions conn)))))
      (should-error
       ;; This stashes the request and waits. It will error because
       ;; no-one clears the "hold deferred" flag.
       (jsonrpc-request conn 'ignore ["first deferred"]
                        :deferred "first deferred"
                        :timeout 0.5)
       :type 'jsonrpc-error)
      ;; The error means the deferred actions stash is now empty
      (should (zerop (hash-table-count (jsonrpc--deferred-actions conn))))
      ;; Again, this returns immediately.
      (jsonrpc-async-request
       conn
       'sit-for [0.1]
       :success-fn
       (lambda (_result)
         ;; This gets run while "third deferred" below is waiting for
         ;; a reply.  Notice that we clear the flag in time here.
         (setq n-deferred-2 (hash-table-count (jsonrpc--deferred-actions conn)))
         (setf (jsonrpc--hold-deferred conn) nil)))
      ;; This again stashes a request and returns immediately.
      (jsonrpc-async-request conn 'ignore ["second deferred"]
                             :deferred "second deferred"
                             :timeout 1
                             :success-fn
                             (lambda (_result)
                               (setq second-deferred-went-through-p t)))
      ;; And this also stashes a request, but waits.  Eventually the
      ;; flag is cleared in time and both requests go through.
      (jsonrpc-request conn 'ignore ["third deferred"]
                       :deferred "third deferred"
                       :timeout 1)
      ;; Wait another 0.5 secs just in case the success handlers of
      ;; one of these last two requests didn't quite have a chance to
      ;; run (Emacs 25.2 apparently needs this).
      (accept-process-output nil 0.5)
      (should second-deferred-went-through-p)
      (should (eq 1 n-deferred-1))
      (should (eq 2 n-deferred-2))
      (should (eq 0 (hash-table-count (jsonrpc--deferred-actions conn)))))))

(provide 'jsonrpc-tests)
;;; jsonrpc-tests.el ends here