[dotnet] Modernize exception handling in tests via assert that throws (#14776)

Author: RenderMichael

dotnet/src/webdriver/WebDriver.cs

@@ -935,7 +935,7 @@ private static object ConvertObjectToJavaScriptObject(object arg)
             }
             else
             {
-                throw new ArgumentException("Argument is of an illegal type" + arg.ToString(), nameof(arg));
+                throw new ArgumentException("Argument is of an illegal type: " + arg.ToString(), nameof(arg));
             }
 
             return converted;

dotnet/test/common/AlertsTest.cs

@@ -60,7 +60,9 @@ public void ShouldThrowArgumentNullExceptionWhenKeysNull()
             IAlert alert = WaitFor<IAlert>(AlertToBePresent, "No alert found");
             try
             {
-                Assert.That(() => alert.SendKeys(null), Throws.ArgumentNullException);
+                Assert.That(
+                    () => alert.SendKeys(null),
+                    Throws.ArgumentNullException);
             }
             finally
             {
@@ -147,13 +149,12 @@ public void SettingTheValueOfAnAlertThrows()
             driver.FindElement(By.Id("alert")).Click();
 
             IAlert alert = WaitFor<IAlert>(AlertToBePresent, "No alert found");
+
             try
             {
-                alert.SendKeys("cheese");
-                Assert.Fail("Expected exception");
-            }
-            catch (ElementNotInteractableException)
-            {
+                Assert.That(
+                    () => alert.SendKeys("cheese"),
+                    Throws.TypeOf<ElementNotInteractableException>());
             }
             finally
             {
@@ -198,8 +199,10 @@ public void AlertShouldNotAllowAdditionalCommandsIfDismissed()
 
             IAlert alert = WaitFor<IAlert>(AlertToBePresent, "No alert found");
             alert.Dismiss();
-            string text;
-            Assert.That(() => text = alert.Text, Throws.InstanceOf<NoAlertPresentException>());
+
+            Assert.That(
+                () => alert.Text,
+                Throws.TypeOf<NoAlertPresentException>());
         }
 
         [Test]
@@ -249,7 +252,9 @@ public void SwitchingToMissingAlertThrows()
         {
             driver.Url = CreateAlertPage("cheese");
 
-            Assert.That(() => AlertToBePresent(), Throws.InstanceOf<NoAlertPresentException>());
+            Assert.That(
+                () => AlertToBePresent(),
+                Throws.TypeOf<NoAlertPresentException>());
         }
 
         [Test]
@@ -270,15 +275,9 @@ public void SwitchingToMissingAlertInAClosedWindowThrows()
                 driver.Close();
                 WaitFor(WindowHandleCountToBe(1), "Window count was not 1");
 
-                try
-                {
-                    AlertToBePresent().Accept();
-                    Assert.Fail("Expected exception");
-                }
-                catch (NoSuchWindowException)
-                {
-                    // Expected
-                }
+                Assert.That(
+                    () => AlertToBePresent().Accept(),
+                    Throws.TypeOf<NoSuchWindowException>());
 
             }
             finally
@@ -321,17 +320,22 @@ public void HandlesTwoAlertsFromOneInteraction()
         {
             driver.Url = EnvironmentManager.Instance.UrlBuilder.CreateInlinePage(new InlinePage()
                 .WithScripts(
-                    "function setInnerText(id, value) {",
-                    "  document.getElementById(id).innerHTML = '<p>' + value + '</p>';",
-                    "}",
-                    "function displayTwoPrompts() {",
-                    "  setInnerText('text1', prompt('First'));",
-                    "  setInnerText('text2', prompt('Second'));",
-                    "}")
+                    """
+                    function setInnerText(id, value) {
+                      document.getElementById(id).innerHTML = '<p>' + value + '</p>';
+                    }
+
+                    function displayTwoPrompts() {
+                      setInnerText('text1', prompt('First'));
+                      setInnerText('text2', prompt('Second'));
+                    }
+                    """)
                 .WithBody(
-                    "<a href='#' id='double-prompt' onclick='displayTwoPrompts();'>click me</a>",
-                    "<div id='text1'></div>",
-                    "<div id='text2'></div>"));
+                    """
+                    <a href='#' id='double-prompt' onclick='displayTwoPrompts();'>click me</a>
+                    <div id='text1'></div>
+                    <div id='text2'></div>
+                    """));
 
             driver.FindElement(By.Id("double-prompt")).Click();
 
@@ -355,7 +359,7 @@ public void HandlesTwoAlertsFromOneInteraction()
         public void ShouldHandleAlertOnPageLoad()
         {
             string pageWithOnLoad = EnvironmentManager.Instance.UrlBuilder.CreateInlinePage(new InlinePage()
-                .WithOnLoad("javascript:alert(\"onload\")")
+                .WithOnLoad("""javascript:alert("onload")""")
                 .WithBody("<p>Page with onload event handler</p>"));
             driver.Url = EnvironmentManager.Instance.UrlBuilder.CreateInlinePage(new InlinePage()
                 .WithBody(string.Format("<a id='open-page-with-onload-alert' href='{0}'>open new page</a>", pageWithOnLoad)));
@@ -411,17 +415,12 @@ public void ShouldNotHandleAlertInAnotherWindow()
                 Assert.AreEqual(1, allWindows.Count);
                 onloadWindow = allWindows[0];
 
-                try
+                Assert.That(() =>
                 {
                     IWebElement el = driver.FindElement(By.Id("open-new-window"));
                     WaitFor<IAlert>(AlertToBePresent, TimeSpan.FromSeconds(5), "No alert found");
-                    Assert.Fail("Expected exception");
-                }
-                catch (WebDriverException)
-                {
-                    // An operation timed out exception is expected,
-                    // since we're using WaitFor<T>.
-                }
+                },
+                Throws.TypeOf<WebDriverException>());
 
             }
             finally
@@ -442,15 +441,10 @@ public void IncludesAlertTextInUnhandledAlertException()
 
             driver.FindElement(By.Id("alert")).Click();
             WaitFor<IAlert>(AlertToBePresent, "No alert found");
-            try
-            {
-                string title = driver.Title;
-                Assert.Fail("Expected UnhandledAlertException");
-            }
-            catch (UnhandledAlertException e)
-            {
-                Assert.AreEqual("cheese", e.AlertText);
-            }
+
+            Assert.That(
+                () => driver.Title,
+                Throws.TypeOf<UnhandledAlertException>().With.Property(nameof(UnhandledAlertException.AlertText)).EqualTo("cheese"));
         }
 
         [Test]
@@ -522,16 +516,14 @@ private Func<IWebElement> ElementToBePresent(By locator)
         {
             return () =>
             {
-                IWebElement foundElement = null;
                 try
                 {
-                    foundElement = driver.FindElement(By.Id("open-page-with-onunload-alert"));
+                    return driver.FindElement(By.Id("open-page-with-onunload-alert"));
                 }
                 catch (NoSuchElementException)
                 {
+                    return null;
                 }
-
-                return foundElement;
             };
         }
 
@@ -554,9 +546,8 @@ private Func<bool> WindowWithName(string name)
                 }
                 catch (NoSuchWindowException)
                 {
+                    return false;
                 }
-
-                return false;
             };
         }
 

dotnet/test/common/CorrectEventFiringTest.cs

@@ -348,20 +348,12 @@ public void SendingKeysToAFocusedElementShouldNotBlurThatElement()
                     focused = true;
                     break;
                 }
-                try
-                {
-                    System.Threading.Thread.Sleep(200);
-                }
-                catch (Exception)
-                {
-                    throw;
-                }
-            }
-            if (!focused)
-            {
-                Assert.Fail("Clicking on element didn't focus it in time - can't proceed so failing");
+
+                System.Threading.Thread.Sleep(200);
             }
 
+            Assert.That(focused, Is.True, "Clicking on element didn't focus it in time - can't proceed so failing");
+
             element.SendKeys("a");
             AssertEventNotFired("blur");
         }

dotnet/test/common/ElementAttributeTest.cs

@@ -127,28 +127,19 @@ public void ShouldThrowExceptionIfSendingKeysToElementDisabledUsingRandomDisable
         {
             driver.Url = formsPage;
             IWebElement disabledTextElement1 = driver.FindElement(By.Id("disabledTextElement1"));
-            try
+
+            Assert.That(() =>
             {
                 disabledTextElement1.SendKeys("foo");
-                Assert.Fail("Should have thrown exception");
-            }
-            catch (InvalidElementStateException)
-            {
-                //Expected
-            }
+            }, Throws.TypeOf<ElementNotInteractableException>());
 
             Assert.AreEqual(string.Empty, disabledTextElement1.Text);
 
             IWebElement disabledTextElement2 = driver.FindElement(By.Id("disabledTextElement2"));
-            try
-            {
-                disabledTextElement2.SendKeys("bar");
-                Assert.Fail("Should have thrown exception");
-            }
-            catch (InvalidElementStateException)
-            {
-                //Expected
-            }
+
+            Assert.That(
+                () => disabledTextElement2.SendKeys("bar"),
+                Throws.TypeOf<ElementNotInteractableException>());
 
             Assert.AreEqual(string.Empty, disabledTextElement2.Text);
         }

dotnet/test/common/Environment/RemoteSeleniumServer.cs

@@ -91,14 +91,15 @@ public async Task StopAsync()
         {
             if (autoStart && webserverProcess != null && !webserverProcess.HasExited)
             {
-                using var httpClient = new HttpClient();
-
-                try
-                {
-                    using var response = await httpClient.GetAsync("http://localhost:6000/selenium-server/driver?cmd=shutDownSeleniumServer");
-                }
-                catch (Exception ex) when (ex is HttpRequestException || ex is TimeoutException)
+                using (var httpClient = new HttpClient())
                 {
+                    try
+                    {
+                        using var response = await httpClient.GetAsync("http://localhost:6000/selenium-server/driver?cmd=shutDownSeleniumServer");
+                    }
+                    catch (Exception ex) when (ex is HttpRequestException || ex is TimeoutException)
+                    {
+                    }
                 }
 
                 webserverProcess.WaitForExit(10000);