test_soft_reload.py

from selenium.webdriver.support.select import Select
import time, os


RED_BG = """
#hot-reload-content {
    background-color: red;
}
"""


app = """
library(dash)
app <- Dash$new()

app$layout(html$div(list(
html$h3("Hot reload"),
dccInput(id='input'),
html$div(id='output-serverside')
),
id="hot-reload-content"
)
)

app$callback(
  output(id = "output-serverside", property = "children"),
  params = list(
    input(id = "input", property = "value")
  ),
  function(value) {
    sprintf("Test output should be %s", value)
  }
)

app$run_server(dev_tools_hot_reload=TRUE, dev_tools_hot_reload_interval=0.1, dev_tools_silence_routes_logging=TRUE)
"""


def test_rsdv001_soft_reload(dashr):
    dashr.start_server(app)
    dashr.wait_for_style_to_equal(
        "#hot-reload-content",
        "background-color",
        "rgba(0, 0, 255, 1)"
    )
    dashr.wait_for_text_to_equal(
        "#output-serverside",
        "Test output should be NULL"
    )
    input1 = dashr.find_element("#input")
    dashr.clear_input(input1)
    input1.send_keys("unchanged")
    hot_reload_file = os.path.join(
        dashr.server.tmp_app_path, "assets", "hot_reload.css"
    )
    print(hot_reload_file)
    with open(hot_reload_file, "r+") as fp:
        time.sleep(1)  # ensure a new mod time
        old_content = fp.read()
        fp.truncate(0)
        fp.seek(0)
        fp.write(RED_BG)
    dashr.wait_for_style_to_equal(
        "#hot-reload-content",
        "background-color",
        "rgba(255, 0, 0, 1)"
    )
    dashr.wait_for_text_to_equal(
        "#output-serverside",
        "Test output should be unchanged"
    )
    with open(hot_reload_file, "w") as f:
        f.write(old_content)
        time.sleep(1)
    dashr.wait_for_style_to_equal(
        "#hot-reload-content",
        "background-color",
        "rgba(0, 0, 255, 1)"
    )