Fix up O# tests

Author: JoeRobich

test/lsptoolshost/unitTests/migrateOptions.test.ts

@@ -18,6 +18,7 @@ import { getVSCodeWithConfig } from '../../fakes';
 import { CSharpExtensionId } from '../../../src/constants/csharpExtensionId';
 import { ConfigurationTarget } from '../../../src/vscodeAdapter';
 
+// Necessary when spying on module members.
 jest.mock('fs', () => ({ __esModule: true, ...(<any>jest.requireActual('fs')) }));
 
 describe('Migrate configurations', () => {

test/omnisharp/omnisharpUnitTests/features/reportIssue.test.ts

@@ -62,11 +62,7 @@ describe(`${reportIssue.name}`, () => {
             issueBody = rest[0].issueBody;
             return {} as any;
         });
-        jest.replaceProperty(vscode, 'extensions', {
-            all: [extension1, extension2],
-            getExtension: jest.fn(),
-            onDidChange: jest.fn(),
-        } as typeof vscode.extensions);
+        jest.replaceProperty(vscode.extensions, "all", [extension1, extension2] as readonly vscode.Extension<any>[]);
 
         fakeMonoResolver = new FakeMonoResolver();
         fakeDotnetResolver = new FakeDotnetResolver();

test/omnisharp/omnisharpUnitTests/packages/packageFilterer.test.ts

@@ -11,6 +11,9 @@ import { MockedFunction } from 'jest-mock';
 import * as fs from 'fs';
 import { join } from 'path';
 
+// Necessary when spying on module members.
+jest.mock('fs', () => ({ __esModule: true, ...(<any>jest.requireActual('fs')) }));
+
 describe(`${getNotInstalledPackagesForPlatform.name}`, () => {
     let absolutePathPackages: AbsolutePathPackage[];
     const extensionPath = '/ExtensionPath';