test: fix unit test case (#14285)

* test: update test case

* test: fix test cases

* test: fix test cases

Author: wenytang-ms

packages/fx-core/tests/component/driver/script/scriptDriver.test.ts

@@ -352,29 +352,30 @@ describe("getStderrHandler", () => {
 
 describe("defaultShell", () => {
   const sandbox = sinon.createSandbox();
-  let restoreEnv: RestoreFn = () => {};
   afterEach(() => {
     sandbox.restore();
-    restoreEnv();
   });
   it("SHELL", async () => {
-    restoreEnv = mockedEnv({ SHELL: "/bin/bash" });
+    sandbox.stub(process, "env").value({ SHELL: "/bin/bash" });
     const result = await defaultShell();
     assert.equal(result, "/bin/bash");
   });
   it("darwin - /bin/zsh", async () => {
+    sandbox.stub(process, "env").value({});
     sandbox.stub(process, "platform").value("darwin");
     sandbox.stub(fs, "pathExists").resolves(true);
     const result = await defaultShell();
     assert.equal(result, "/bin/zsh");
   });
   it("darwin - /bin/bash", async () => {
+    sandbox.stub(process, "env").value({});
     sandbox.stub(process, "platform").value("darwin");
     sandbox.stub(fs, "pathExists").onFirstCall().resolves(false).onSecondCall().resolves(true);
     const result = await defaultShell();
     assert.equal(result, "/bin/bash");
   });
   it("darwin - undefined", async () => {
+    sandbox.stub(process, "env").value({});
     sandbox.stub(process, "platform").value("darwin");
     sandbox.stub(fs, "pathExists").resolves(false);
     const result = await defaultShell();
@@ -383,25 +384,27 @@ describe("defaultShell", () => {
 
   it("win32 - ComSpec", async () => {
     sandbox.stub(process, "platform").value("win32");
-    restoreEnv = mockedEnv({ ComSpec: "cmd.exe" });
+    sandbox.stub(process, "env").value({ ComSpec: "cmd.exe" });
     const result = await defaultShell();
     assert.equal(result, "cmd.exe");
   });
   it("win32 - cmd.exe", async () => {
     sandbox.stub(process, "platform").value("win32");
-    restoreEnv = mockedEnv({ ComSpec: undefined });
+    sandbox.stub(process, "env").value({});
     const result = await defaultShell();
     assert.equal(result, "cmd.exe");
   });
 
   it("other OS - /bin/sh", async () => {
+    sandbox.stub(process, "env").value({});
     sandbox.stub(process, "platform").value("other");
     sandbox.stub(fs, "pathExists").resolves(true);
     const result = await defaultShell();
     assert.equal(result, "/bin/sh");
   });
 
   it("other OS - undefined", async () => {
+    sandbox.stub(process, "env").value({});
     sandbox.stub(process, "platform").value("other");
     sandbox.stub(fs, "pathExists").resolves(false);
     const result = await defaultShell();