Implement ElementHandle.QuerySelectorAsync (a.k.a. $) (#218)

Meir017 · kblok · commit 4c106f373499 · 2018-05-11T08:32:33.000-03:00
diff --git a/lib/PuppeteerSharp.Tests/ElementHandleTests/QuerySelectorTests.cs b/lib/PuppeteerSharp.Tests/ElementHandleTests/QuerySelectorTests.cs
@@ -0,0 +1,31 @@
+using System;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace PuppeteerSharp.Tests.ElementHandleTests
+{
+    [Collection("PuppeteerLoaderFixture collection")]
+    public class QuerySelectorTests : PuppeteerPageBaseTest
+    {
+        [Fact]
+        public async Task ShouldQueryExistingElement()
+        {
+            await Page.GoToAsync(TestConstants.ServerUrl + "/playground.html");
+            await Page.SetContentAsync("<html><body><div class=\"second\"><div class=\"inner\">A</div></div></body></html>");
+            var html = await Page.QuerySelectorAsync("html");
+            var second = await html.QuerySelectorAsync(".second");
+            var inner = await second.QuerySelectorAsync(".inner");
+            var content = await Page.EvaluateFunctionAsync<string>("e => e.textContent", inner);
+            Assert.Equal("A", content);
+        }
+
+        [Fact]
+        public async Task ShouldReturnNullForNonExistingElement()
+        {
+            await Page.SetContentAsync("<html><body><div class=\"second\"><div class=\"inner\">B</div></div></body></html>");
+            var html = await Page.QuerySelectorAsync("html");
+            var second = await html.QuerySelectorAsync(".third");
+            Assert.Null(second);
+        }
+    }
+}
diff --git a/lib/PuppeteerSharp/ElementHandle.cs b/lib/PuppeteerSharp/ElementHandle.cs
@@ -176,7 +176,12 @@ public async Task PressAsync(string key, PressOptions options = null)
             await Page.Keyboard.PressAsync(key, options);
         }
 
-        internal async Task<ElementHandle> QuerySelectorAsync(string selector)
+        /// <summary>
+        /// The method runs <c>element.querySelector</c> within the page. If no element matches the selector, the return value resolve to <c>null</c>.
+        /// </summary>
+        /// <param name="selector">A selector to query element for</param>
+        /// <returns>Task which resolves to <see cref="ElementHandle"/> pointing to the frame element</returns>
+        public async Task<ElementHandle> QuerySelectorAsync(string selector)
         {
             var handle = await ExecutionContext.EvaluateFunctionHandleAsync(
                 "(element, selector) => element.querySelector(selector)",

Original file line number	Diff line number	Diff line change
`@@ -176,7 +176,12 @@ public async Task PressAsync(string key, PressOptions options = null)`
`176`	`176`	`await Page.Keyboard.PressAsync(key, options);`
`177`	`177`	`}`
`178`	`178`
`179`		`- internal async Task<ElementHandle> QuerySelectorAsync(string selector)`
	`179`	`+ /// <summary>`
	`180`	`+ /// The method runs <c>element.querySelector</c> within the page. If no element matches the selector, the return value resolve to <c>null</c>.`
	`181`	`+ /// </summary>`
	`182`	`+ /// <param name="selector">A selector to query element for</param>`
	`183`	`+ /// <returns>Task which resolves to <see cref="ElementHandle"/> pointing to the frame element</returns>`
	`184`	`+ public async Task<ElementHandle> QuerySelectorAsync(string selector)`
`180`	`185`	`{`
`181`	`186`	`var handle = await ExecutionContext.EvaluateFunctionHandleAsync(`
`182`	`187`	`"(element, selector) => element.querySelector(selector)",`