Async browser.newContext

About the TestK6Object update:
- To prevent race conditions, the JavaScript codes in the tests run in
  the event loop.

browser/browser_mapping.go

@@ -6,11 +6,11 @@ import (
 	"github.com/dop251/goja"
 
 	"github.com/grafana/xk6-browser/common"
+	"github.com/grafana/xk6-browser/k6ext"
 )
 
 // mapBrowser to the JS module.
 func mapBrowser(vu moduleVU) mapping { //nolint:funlen,cyclop
-	rt := vu.Runtime()
 	return mapping{
 		"context": func() (mapping, error) {
 			b, err := vu.browser()
@@ -33,23 +33,25 @@ func mapBrowser(vu moduleVU) mapping { //nolint:funlen,cyclop
 			}
 			return b.IsConnected(), nil
 		},
-		"newContext": func(opts goja.Value) (*goja.Object, error) {
-			b, err := vu.browser()
-			if err != nil {
-				return nil, err
-			}
-			bctx, err := b.NewContext(opts)
-			if err != nil {
-				return nil, err //nolint:wrapcheck
-			}
+		"newContext": func(opts goja.Value) (*goja.Promise, error) {
+			return k6ext.Promise(vu.Context(), func() (any, error) {
+				b, err := vu.browser()
+				if err != nil {
+					return nil, err
+				}
+				bctx, err := b.NewContext(opts)
+				if err != nil {
+					return nil, err //nolint:wrapcheck
+				}
 
-			if err := initBrowserContext(bctx, vu.testRunID); err != nil {
-				return nil, err
-			}
+				if err := initBrowserContext(bctx, vu.testRunID); err != nil {
+					return nil, err
+				}
 
-			m := mapBrowserContext(vu, bctx)
+				m := mapBrowserContext(vu, bctx)
 
-			return rt.ToValue(m).ToObject(rt), nil
+				return m, nil
+			}), nil
 		},
 		"userAgent": func() (string, error) {
 			b, err := vu.browser()

tests/browser_context_test.go

@@ -10,6 +10,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/dop251/goja"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -651,30 +652,35 @@ func TestK6Object(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 
-			_, rt, _, cleanUp := startIteration(t, env.ConstLookup(env.K6TestRunID, tt.testRunID))
+			vu, _, _, cleanUp := startIteration(t, env.ConstLookup(env.K6TestRunID, tt.testRunID))
 			defer cleanUp()
 
 			// First test with browser.newPage
-			got, err := rt.RunString(`
-				const p = browser.newPage()
-				p.goto("about:blank")
-				const o = p.evaluate(() => window.k6)
-				JSON.stringify(o)
+			got, err := vu.TestRT.RunOnEventLoop(`
+				const p = browser.newPage();
+				p.goto("about:blank");
+				const o = p.evaluate(() => window.k6);
+				JSON.stringify(o);
 			`)
 			require.NoError(t, err)
 			assert.Equal(t, tt.want, got.String())
 
 			// Now test with browser.newContext
-			got, err = rt.RunString(`
-				browser.closeContext()
-				const c = browser.newContext()
-				const p2 = c.newPage()
-				p2.goto("about:blank")
-				const o2 = p2.evaluate(() => window.k6)
-				JSON.stringify(o2)
+			got, err = vu.TestRT.RunOnEventLoop(`
+				const test = async function() {
+					browser.closeContext();
+					const c = await browser.newContext();
+					const p2 = c.newPage();
+					p2.goto("about:blank");
+					const o2 = p2.evaluate(() => window.k6);
+					return JSON.stringify(o2);
+				}
+				test();
 			`)
 			require.NoError(t, err)
-			assert.Equal(t, tt.want, got.String())
+			p, ok := got.Export().(*goja.Promise)
+			require.Truef(t, ok, "got: %T, want *goja.Promise", got.Export())
+			assert.Equal(t, tt.want, p.Result().String())
 		})
 	}
 }