samhennessy/hlive/hlive-testing

HLive Testing

HLive's behavior lives in the browser round-trip, so it's tested by driving a real browser with Playwright via the hlivetest package. Tests boot an HLive server, open a browser page against it, interact, and assert on the resulting DOM.

Setup

Tests need Playwright browsers installed:

make install-test
# or: go run github.com/playwright-community/playwright-go/cmd/playwright install --with-deps

Because these are heavy browser tests, guard them so go test -short skips them (the harness below does this).

The harness pattern

HLive's own suite (hlivetest/pages/) uses a small per-package harness. Copy it into your test package:

package pages_test
 
import (
    "testing"
 
    l "github.com/SamHennessy/hlive"
    "github.com/SamHennessy/hlive/hlivetest"
    "github.com/playwright-community/playwright-go"
)
 
type harness struct {
    server   *hlivetest.Server
    pwpage   playwright.Page
    teardown func()
}
 
func setup(t *testing.T, pageFn func() *l.Page) harness {
    t.Helper()
 
    if testing.Short() {
        t.Skip("skipping test in short mode.")
    }
 
    h := harness{
        server: hlivetest.NewServer(pageFn),
        pwpage: hlivetest.NewBrowserPage(),
    }
 
    h.teardown = func() {
        if err := h.pwpage.Close(); err != nil {
            t.Error(err)
        }
    }
 
    if _, err := h.pwpage.Goto(h.server.HTTPServer.URL); err != nil {
        t.Fatal("goto page:", err)
    }
 
    return h
}

NewServer takes a page factory (func() *l.Page) — the same kind of function you hand to l.NewPageServer. In a structured app (see the hlive-project skill) that's an exported factory from your page package, so a test imports it and passes it straight in: setup(t, page.Home).

Give the elements you select stable ids. With hhtml use the Id(...) attribute:

import (
    l "github.com/SamHennessy/hlive"
    . "github.com/SamHennessy/hlive/hhtml"
)
 
func Counter() *l.Page {
    count := l.Box(0)
    page := l.NewPage()
    page.DOM().Body().Add(
        Button(Id("btn"), l.On("click", func(_ context.Context, _ l.Event) {
            count.Lock(func(v int) int { return v + 1 })
        }), "+"),
        Div(Id("count"), count),
    )
    return page
}

Writing a test

func TestClick_OneClick(t *testing.T) {
    t.Parallel()
 
    h := setup(t, pages.Click()) // pages.Click() returns the page factory
    defer h.teardown()
 
    hlivetest.Diff(t, "0", hlivetest.TextContent(t, h.pwpage, "#count"))
 
    hlivetest.ClickAndWait(t, h.pwpage, "#btn") // click, then wait for the diff
 
    hlivetest.Diff(t, "1", hlivetest.TextContent(t, h.pwpage, "#count"))
}

Use ClickAndWait before an assertion (it waits for HLive's diff to apply). Use plain Click for intermediate clicks where you'll assert only at the end:

for i := 0; i < 9; i++ {
    hlivetest.Click(t, h.pwpage, "#btn")
}
hlivetest.ClickAndWait(t, h.pwpage, "#btn")
hlivetest.Diff(t, "10", hlivetest.TextContent(t, h.pwpage, "#count"))

hlivetest helpers

All take (t, pwpage, ...) unless noted:

• Click(selector) — click without waiting for the diff.
• ClickAndWait(selector) — click, then block until the diff is applied.
• TextContent(selector) string — element text.
• GetAttribute(selector, attribute) string — an attribute value.
• GetID(selector) string — the element's HLive id.
• Title(pwpage) string — page title.
• Diff(want, got any) — assert equal, reporting a diff on failure (t.Error).
• DiffFatal(want, got any) — same but t.Fatal.
• FatalOnErr(err) — fail fast on an error.
• NewServer(pageFn) *Server / NewBrowserPage() playwright.Page — fixtures.

For interactions hlivetest doesn't wrap (typing, hover, selects), use the playwright.Page directly (h.pwpage.Fill(...), .Hover(...)), then assert with hlivetest.Diff.

Running

go test ./...          # full run (needs browsers)
go test -short ./...   # skips the browser tests

Reference

hlivetest/hlivetest.go, hlivetest/server.go, hlivetest/browser.go, and the examples hlivetest/pages/harness_test.go, hlivetest/pages/click_test.go, hlivetest/pages/click.go. Larger suites live under systemtests/.