JSEnv and chekhov-dom

#Wire ChekhovJSEnv

Published consumers: add the plugin (it depends on chekhov-jsenv) and set jsEnv:

// project/plugins.sbt
addSbtPlugin("rocks.earlyeffect" % "sbt-chekhov" % "<version>")

// build.sbt
import chekhov.sbt.ChekhovPlugin.autoImport.*

libraryDependencies += "rocks.earlyeffect" %%% "chekhov-dom" % "<version>" % Test
Test / jsEnv := chekhovJSEnv.value
// or: Test / jsEnv := ChekhovJSEnv()
// or: Test / jsEnv := ChekhovJSEnv(ChekhovBrowser.Firefox)

Prefer ModuleKind.ESModule (or otherwise materializable scripts) for linked test output. ChekhovJSEnv materializes Input.Script / Input.ESModule onto a localhost page and bridges scalajsCom via frame evaluateExpression.

This monorepo still uses an internal classpath bridge for jsenv-smoke / dom so CI need not publish first. Consumers should not copy that bridge.

#chekhov-dom helpers

import chekhov.dom.ChekhovDom.*
import zio.test.*

test("focus") {
  withRoot { root =>
    for
      _     <- ZIO.succeed(/* mount UI under root */)
      _     <- getByRole("textbox", root).click
      start <- getByRole("textbox", root).selectionStart
    yield assertTrue(start >= 0)
  }
}

withRoot installs a scoped throwaway parent under document.body. Locators cover testid / role / CSS; waitFor polls until the node appears. Depend on org.scala-js:::scalajs-dom only (not ascent’s DOM facade).

#Isolation: one page per module

ChekhovJSEnv hosts the whole module's compiled test bundle in one Playwright page, shared by every spec and test in the module (ZIO Test runs them concurrently).

• withRoot installs each scope inside its own iframe, so scoped DOM work is isolated from sibling scopes. Pass the scoped root to locators (getByTestId("inc", root)), not the whole document.

• The parent document is still shared: whole-document assertions (element counts, global state) can observe a sibling test mid-flight and flake. Assert on your own element: capture the root inside the scope and check it after exit.

test("count starts at zero") {
  withRoot { root =>
    for
      _ <- ZIO.succeed(mount(ui))
      t <- getByTestId("count", root).innerText
    yield assertTrue(t == "0")
  }
}

#chekhov-ascent

Ascent UI under JSEnv lives in chekhov-ascent (ChekhovAscent.withMounted), not core. It mounts into a chekhov-dom root and tears down via ascent’s subscription bag:

libraryDependencies += "rocks.earlyeffect" %%% "chekhov-ascent" % "<version>" % Test

import chekhov.ascent.ChekhovAscent.withMounted
import chekhov.dom.*

withMounted(ui) { root =>
  getByTestId("inc", root).click
}

Use chekhov-dom alone when you do not need ascent.

#Smoke in this repo

sbt 'jsenv/testOnly chekhov.jsenv.JsEnvComSpec'
sbt jsenv-smoke/testFull
sbt dom/testFull
sbt ascent/testFull

ChekhovBrowser.fromString("firefox").map(_.channelName)

Some(firefox)