Merge pull request #827 from plotly/dashr-test-support

Dashr test support

Author: byronz

Diff for: dash/CHANGELOG.md

@@ -1,3 +1,9 @@
+## Unreleased
+
+### Added
+
+- [#827](https://github.com/plotly/dash/pull/827) Adds support for dashR testing using pytest framework
+
 ## [1.0.2] - 2019-07-15
 ### Fixed
 - [#821](https://github.com/plotly/dash/pull/821) Fix a bug with callback error reporting, [#791](https://github.com/plotly/dash/issues/791).

Diff for: dash/testing/application_runners.py

@@ -1,6 +1,7 @@
 from __future__ import print_function
 
 import sys
+import os
 import uuid
 import shlex
 import threading
@@ -68,6 +69,14 @@ def start(self, *args, **kwargs):
     def stop(self):
         raise NotImplementedError  # pragma: no cover
 
+    @staticmethod
+    def accessible(url):
+        try:
+            requests.get(url)
+        except requests.exceptions.RequestException:
+            return False
+        return True
+
     def __call__(self, *args, **kwargs):
         return self.start(*args, **kwargs)
 
@@ -91,6 +100,10 @@ def url(self):
         """the default server url"""
         return "http://localhost:{}".format(self.port)
 
+    @property
+    def is_windows(self):
+        return sys.platform == "win32"
+
 
 class ThreadedRunner(BaseDashRunner):
     """Runs a dash application in a thread
@@ -145,15 +158,8 @@ def run():
 
         self.started = self.thread.is_alive()
 
-        def accessible():
-            try:
-                requests.get(self.url)
-            except requests.exceptions.RequestException:
-                return False
-            return True
-
         # wait until server is able to answer http request
-        wait.until(accessible, timeout=1)
+        wait.until(lambda: self.accessible(self.url), timeout=1)
 
     def stop(self):
         requests.get("{}{}".format(self.url, self.stop_route))
@@ -180,14 +186,17 @@ def start(self, app_module, application_name="app", port=8050):
 
         args = shlex.split(
             "waitress-serve --listen=0.0.0.0:{} {}".format(port, entrypoint),
-            posix=sys.platform != "win32",
+            posix=not self.is_windows,
         )
         logger.debug("start dash process with %s", args)
 
         try:
             self.proc = subprocess.Popen(
                 args, stdout=subprocess.PIPE, stderr=subprocess.PIPE
             )
+            # wait until server is able to answer http request
+            wait.until(lambda: self.accessible(self.url), timeout=3)
+
         except (OSError, ValueError):
             logger.exception("process server has encountered an error")
             self.started = False
@@ -214,3 +223,55 @@ def stop(self):
                 )
                 self.proc.kill()
                 self.proc.communicate()
+
+
+class RRunner(ProcessRunner):
+    def __init__(self, keep_open=False, stop_timeout=3):
+        super(RRunner, self).__init__(
+            keep_open=keep_open, stop_timeout=stop_timeout
+        )
+        self.proc = None
+
+    # pylint: disable=arguments-differ
+    def start(self, app):
+        """Start the server with waitress-serve in process flavor """
+
+        # app is a R string chunk
+        if not (os.path.isfile(app) and os.path.exists(app)):
+            path = (
+                "/tmp/app_{}.R".format(uuid.uuid4().hex)
+                if not self.is_windows
+                else os.path.join(
+                    (os.getenv("TEMP"), "app_{}.R".format(uuid.uuid4().hex))
+                )
+            )
+            logger.info("RRuner start => app is R code chunk")
+            logger.info("make a temporay R file for execution=> %s", path)
+            logger.debug("the content of dashR app")
+            logger.debug("%s", app)
+
+            with open(path, "w") as fp:
+                fp.write(app)
+
+            app = path
+
+        logger.info("Run dashR app with Rscript => %s", app)
+        args = shlex.split(
+            "Rscript {}".format(os.path.realpath(app)),
+            posix=not self.is_windows,
+        )
+        logger.debug("start dash process with %s", args)
+
+        try:
+            self.proc = subprocess.Popen(
+                args, stdout=subprocess.PIPE, stderr=subprocess.PIPE
+            )
+            # wait until server is able to answer http request
+            wait.until(lambda: self.accessible(self.url), timeout=2)
+
+        except (OSError, ValueError):
+            logger.exception("process server has encountered an error")
+            self.started = False
+            return
+
+        self.started = True

Diff for: dash/testing/composite.py

@@ -14,3 +14,17 @@ def start_server(self, app, **kwargs):
 
         # set the default server_url, it implicitly call wait_for_page
         self.server_url = self.server.url
+
+
+class DashRComposite(Browser):
+    def __init__(self, server, **kwargs):
+        super(DashRComposite, self).__init__(**kwargs)
+        self.server = server
+
+    def start_server(self, app):
+
+        # start server with dashR app, the dash arguments are hardcoded
+        self.server(app)
+
+        # set the default server_url, it implicitly call wait_for_page
+        self.server_url = self.server.url

Diff for: dash/testing/plugin.py

@@ -4,9 +4,13 @@
 try:
     import pytest
 
-    from dash.testing.application_runners import ThreadedRunner, ProcessRunner
+    from dash.testing.application_runners import (
+        ThreadedRunner,
+        ProcessRunner,
+        RRunner,
+    )
     from dash.testing.browser import Browser
-    from dash.testing.composite import DashComposite
+    from dash.testing.composite import DashComposite, DashRComposite
 except ImportError:
     warnings.warn("run `pip install dash[testing]` if you need dash.testing")
 
@@ -26,9 +30,7 @@ def pytest_addoption(parser):
     )
 
     dash.addoption(
-        "--headless",
-        action="store_true",
-        help="Run tests in headless mode",
+        "--headless", action="store_true", help="Run tests in headless mode"
     )
 
 
@@ -79,13 +81,19 @@ def dash_process_server():
         yield starter
 
 
+@pytest.fixture
+def dashr_server():
+    with RRunner() as starter:
+        yield starter
+
+
 @pytest.fixture
 def dash_br(request, tmpdir):
     with Browser(
         browser=request.config.getoption("webdriver"),
         headless=request.config.getoption("headless"),
         options=request.config.hook.pytest_setup_options(),
-        download_path=tmpdir.mkdir('download').strpath
+        download_path=tmpdir.mkdir("download").strpath,
     ) as browser:
         yield browser
 
@@ -97,6 +105,18 @@ def dash_duo(request, dash_thread_server, tmpdir):
         browser=request.config.getoption("webdriver"),
         headless=request.config.getoption("headless"),
         options=request.config.hook.pytest_setup_options(),
-        download_path=tmpdir.mkdir('download').strpath
+        download_path=tmpdir.mkdir("download").strpath,
+    ) as dc:
+        yield dc
+
+
+@pytest.fixture
+def dashr(request, dashr_server, tmpdir):
+    with DashRComposite(
+        dashr_server,
+        browser=request.config.getoption("webdriver"),
+        headless=request.config.getoption("headless"),
+        options=request.config.hook.pytest_setup_options(),
+        download_path=tmpdir.mkdir("download").strpath,
     ) as dc:
         yield dc

Diff for: tests/unit/test_app_runners.py

@@ -1,4 +1,3 @@
-import time
 import sys
 import requests
 import pytest
@@ -27,7 +26,6 @@ def test_threaded_server_smoke(dash_thread_server):
 )
 def test_process_server_smoke(dash_process_server):
     dash_process_server("simple_app")
-    time.sleep(2.5)
     r = requests.get(dash_process_server.url)
     assert r.status_code == 200, "the server is reachable"
     assert 'id="react-entry-point"' in r.text, "the entrypoint is present"