add tests

test/PowerShellEditorServices.Test.Shared/RunspaceSynchronizer/testModule.psm1

@@ -0,0 +1,13 @@
+#
+# Copyright (c) Microsoft. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for full license information.
+#
+
+function Search-Foo {
+    param ()
+    "success"
+}
+
+Set-Alias sfoo Search-Foo
+
+Export-ModuleMember -Function Search-Foo -Alias sfoo

test/PowerShellEditorServices.Test/Language/RunspaceSynchronizerTests.cs

@@ -0,0 +1,65 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.ObjectModel;
+using Xunit;
+
+namespace Microsoft.PowerShell.EditorServices.Test.Language
+{
+    using System.Management.Automation;
+
+    public class RunspaceSynchronizerTests
+    {
+        [Trait("Category", "RunspaceSynchronizer")]
+        [Theory]
+        // variable test
+        [InlineData("$foo = 'foo'", "$foo", "foo")]
+        // module functions test
+        [InlineData("Import-Module ../../../../PowerShellEditorServices.Test.Shared/RunspaceSynchronizer/testModule.psm1", "Search-Foo", "success")]
+        // module aliases test
+        [InlineData("Import-Module ../../../../PowerShellEditorServices.Test.Shared/RunspaceSynchronizer/testModule.psm1", "(Get-Alias sfoo).Definition", "Search-Foo")]
+        public void TestRunspaceSynchronizerSyncsData(string sourceScript, string targetScript, object expected)
+        {
+            using (PowerShell pwshSource = PowerShell.Create())
+            using (PowerShell pwshTarget = PowerShell.Create())
+            {
+                RunspaceSynchronizer.InitializeRunspaces(pwshSource.Runspace, pwshTarget.Runspace);
+                AssertExpectedIsSynced(pwshSource, pwshTarget, sourceScript, targetScript, expected);
+            }
+        }
+
+        [Fact]
+        public void TestRunspaceSynchronizerOverwritesTypes()
+        {
+            using (PowerShell pwshSource = PowerShell.Create())
+            using (PowerShell pwshTarget = PowerShell.Create())
+            {
+                RunspaceSynchronizer.InitializeRunspaces(pwshSource.Runspace, pwshTarget.Runspace);
+                AssertExpectedIsSynced(pwshSource, pwshTarget, "$foo = 444", "$foo.GetType().Name", "Int32");
+                AssertExpectedIsSynced(pwshSource, pwshTarget, "$foo = 'change to string'", "$foo.GetType().Name", "String");
+            }
+        }
+
+        private static void AssertExpectedIsSynced(
+            PowerShell pwshSource,
+            PowerShell pwshTarget,
+            string sourceScript,
+            string targetScript,
+            object expected)
+        {
+            pwshSource.AddScript(sourceScript).Invoke();
+            RunspaceSynchronizer.Activate();
+
+            // We need to allow the event some time to fire.
+            System.Threading.Thread.Sleep(1000);
+
+            var results = pwshTarget.AddScript(targetScript).Invoke<PSObject>();
+
+            Assert.Single(results);
+            Assert.NotNull(results[0].BaseObject);
+            Assert.Equal(expected, results[0].BaseObject);
+        }
+    }
+}