Fix return type of ExecuteScript for Playwright; Add generic overload

src/Coypu.Drivers.Tests/When_executing_script.cs

@@ -1,6 +1,8 @@
 using Coypu.Finders;
 using Shouldly;
 using NUnit.Framework;
+using System;
+using Coypu.Tests;
 
 namespace Coypu.Drivers.Tests
 {
@@ -30,6 +32,27 @@ public void Passes_the_arguments_to_the_browser()
         public void Returns_the_result()
         {
             Driver.ExecuteScript("return document.getElementById('firstButtonId').innerHTML;", Root).ShouldBe("first button");
+            Driver.ExecuteScript("return 1234;", Root).ShouldBe(1234);
+        }
+
+         [Test]
+        public void Returns_the_result_typed()
+        {
+            string str = Driver.ExecuteScript<string>("return 'miles';", Root);
+            str.GetType().ShouldBe(typeof(string));
+
+            int integer = Driver.ExecuteScript<int>("return 1234;", Root);
+            integer.GetType().ShouldBe(typeof(int));
+
+            DateTime dateTime = Driver.ExecuteScript<DateTime>("return new Date();", Root);
+            dateTime.GetType().ShouldBe(typeof(DateTime));
+
+            try {
+              Driver.ExecuteScript<int>("return 'bob';", Root);
+              throw new TestException("Expected an exception");
+            } catch(Exception e) {
+              if (e is TestException) throw;
+            };
         }
     }
 }

src/Coypu.Tests/TestDoubles/FakeDriver.cs

@@ -113,7 +113,14 @@ public object ExecuteScript(string javascript,
                                     Scope scope,
                                     params object[] args)
         {
-            return Find<string>(_stubbedExecuteScriptResults, javascript, scope);
+            return ExecuteScript<string>(javascript, scope, args);
+        }
+
+        public ReturnType ExecuteScript<ReturnType>(string javascript,
+                                    Scope scope,
+                                    params object[] args)
+        {
+            return Find<ReturnType>(_stubbedExecuteScriptResults, javascript, scope);
         }
 
         public IEnumerable<Element> FindFrames(string locator,

src/Coypu.Tests/TestDoubles/StubDriver.cs

@@ -87,6 +87,13 @@ public object ExecuteScript(string javascript,
             return null;
         }
 
+        public ReturnType ExecuteScript<ReturnType>(string javascript,
+                                    Scope scope,
+                                    params object[] args)
+        {
+            return default;
+        }
+
         public void Hover(Element element) { }
 
         public IEnumerable<Cookie> GetBrowserCookies()

src/Coypu/Drivers/Playwright/PlaywrightDriver.cs

@@ -5,6 +5,7 @@
 using System.Text.RegularExpressions;
 using Cookie = System.Net.Cookie;
 using Microsoft.Playwright;
+using OpenQA.Selenium.DevTools.V85.Network;
 
 #pragma warning disable 1591
 
@@ -349,12 +350,18 @@ public void SelectOption(Element select, Element option, string optionToSelect)
         public object ExecuteScript(string javascript,
                                     Scope scope,
                                     params object[] args)
+        {
+            return ExecuteScript<object>(javascript, scope, args);
+        }
+
+        public ReturnType ExecuteScript<ReturnType>(string javascript,
+                                    Scope scope,
+                                    params object[] args)
         {
             var func = $"(arguments) => {Regex.Replace(javascript, "^return ", string.Empty)}";
             return
               PlaywrightPage(scope)
-                .EvaluateAsync(func, ConvertScriptArgs(args)).Sync()
-                .ToString();
+                .EvaluateAsync<ReturnType>(func, ConvertScriptArgs(args)).Sync();
         }
 
         // TODO: extract duplication between Drivers

src/Coypu/Drivers/Selenium/SeleniumWebDriver.cs

@@ -242,12 +242,18 @@ public void SelectOption(Element select, Element option, string optionToSelect)
         public object ExecuteScript(string javascript,
                                     Scope scope,
                                     params object[] args)
+        {
+            return ExecuteScript<object>(javascript, scope, args);
+        }
+        public ReturnType ExecuteScript<ReturnType>(string javascript,
+                                    Scope scope,
+                                    params object[] args)
         {
             if (NoJavascript)
                 throw new NotSupportedException("Javascript is not supported by " + _browser);
 
             _elementFinder.SeleniumScope(scope);
-            return JavaScriptExecutor.ExecuteScript(javascript, ConvertScriptArgs(args));
+            return (ReturnType) JavaScriptExecutor.ExecuteScript(javascript, ConvertScriptArgs(args));
         }
 
         public void Dispose()

src/Coypu/IDriver.cs

@@ -22,6 +22,8 @@ public interface IDriver : IDisposable
         String Title(Scope scope);
         object ExecuteScript(string javascript, Scope scope, params object[] args);
 
+        ReturnType ExecuteScript<ReturnType>(string javascript, Scope scope, params object[] args);
+
         [Obsolete("Please use instead: _browserSession.Driver.Cookies.GetAll()")]
         IEnumerable<Cookie> GetBrowserCookies();