Set test environment variable to prevent double activation

When we add activation on startup finished we encountered a new bug with the test process that has existed for many years
it will activate twice and the extension will be in a bad state. we need to allow manual activation to inject the correct mock classes into the extension and prevent it from activating on startupfinished under test.

vscode-dotnet-runtime-extension/src/extension.ts

@@ -87,9 +87,16 @@ const configPrefix = 'dotnetAcquisitionExtension';
 const displayChannelName = '.NET Runtime';
 const defaultTimeoutValue = 600;
 const moreInfoUrl = 'https://github.com/dotnet/vscode-dotnet-runtime/blob/main/Documentation/troubleshooting-runtime.md';
+let disableActivationUnderTest = true;
 
 export function activate(context: vscode.ExtensionContext, extensionContext?: IExtensionContext)
 {
+
+    if(process.env['DOTNET_INSTALL_TOOL_UNDER_TEST'] === 'true' && disableActivationUnderTest)
+    {
+        return;
+    }
+
     // Loading Extension Configuration
     const extensionConfiguration = extensionContext !== undefined && extensionContext.extensionConfiguration ?
     extensionContext.extensionConfiguration :
@@ -416,3 +423,8 @@ export function activate(context: vscode.ExtensionContext, extensionContext?: IE
         reportIssueRegistration,
         ...eventStreamObservers);
 }
+
+export function allowManualTestActivation()
+{
+    disableActivationUnderTest = false;
+}

vscode-dotnet-runtime-extension/src/test/functional/DotnetCoreAcquisitionExtension.test.ts

@@ -73,6 +73,8 @@ suite('DotnetCoreAcquisitionExtension End to End', function() {
       extensionPath,
       logPath,
     } as any;
+
+    extension.allowManualTestActivation();
     extension.activate(extensionContext, {
       telemetryReporter: new MockTelemetryReporter(),
       extensionConfiguration: new MockExtensionConfiguration([{extensionId: 'alternative.extension', path: 'foo'}], true),

vscode-dotnet-runtime-extension/src/test/functional/runTest.ts

@@ -33,14 +33,18 @@ async function main() {
     }
 
     // Download VS Code, unzip it and run the integration test
-    await runTests({
-      ...(platformValue !== '' && {platform: platformValue}),
-      extensionDevelopmentPath,
-      extensionTestsPath,
-      launchArgs: [
-        // This disables all extensions except the one being testing
-        '--disable-extensions',
-      ]});
+    await runTests(
+      {
+        ...(platformValue !== '' && {platform: platformValue}),
+        extensionDevelopmentPath,
+        extensionTestsPath,
+        launchArgs: [
+          // This disables all extensions except the one being testing
+          '--disable-extensions',
+        ],
+        extensionTestsEnv : { DOTNET_INSTALL_TOOL_UNDER_TEST : 'true' }
+      }
+      );
   } catch (err) {
     console.error('Failed to run tests');
     process.exit(1);