Add FingerprintEnrollProgressViewModelTest

Bug: 259664912
Test: m RunSettingsRoboTests
      ROBOTEST_FILTER=FingerprintEnrollProgressViewModelTest
Change-Id: I10605a9f179c20c3a1ba23373485855a0cbb7099

tests/robotests/src/com/android/settings/testutils/InstantTaskExecutorRule.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.testutils;
+
+import androidx.arch.core.executor.ArchTaskExecutor;
+import androidx.arch.core.executor.TaskExecutor;
+
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
+
+/**
+ * A JUnit Test Rule that swaps the background executor used by the Architecture Components with a
+ * different one which executes each task synchronously.
+ *
+ * We can't refer it in prebuilt androidX library.
+ * Copied it from androidx/arch/core/executor/testing/InstantTaskExecutorRule.java
+ */
+public class InstantTaskExecutorRule extends TestWatcher {
+    @Override
+    protected void starting(Description description) {
+        super.starting(description);
+        ArchTaskExecutor.getInstance().setDelegate(new TaskExecutor() {
+            @Override
+            public void executeOnDiskIO(Runnable runnable) {
+                runnable.run();
+            }
+
+            @Override
+            public void postToMainThread(Runnable runnable) {
+                runnable.run();
+            }
+
+            @Override
+            public boolean isMainThread() {
+                return true;
+            }
+        });
+    }
+
+    @Override
+    protected void finished(Description description) {
+        super.finished(description);
+        ArchTaskExecutor.getInstance().setDelegate(null);
+    }
+}