Convert ReactTestHelper (#37768)

Summary:
As part of the effort to Kotlin-fy React Native tests, I've converted [ReactTestHelper](https://github.com/facebook/react-native/tree/main/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/bridge/ReactTestHelper.java) to Kotlin.

## Changelog:

[Internal] [Changed] - Convert ReactTestHelper to Kotlin

Pull Request resolved: #37768

Test Plan:
Tests pass: ./gradlew :packages:react-native:ReactAndroid:test
Formatted with [KtFmt](https://facebook.github.io/ktfmt/)

Reviewed By: rshest

Differential Revision: D46587427

Pulled By: cortinico

fbshipit-source-id: 82d08d01cf4c7cb7c05a63696e1acdacf60b1ad5

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/bridge/ReactTestHelper.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.bridge
+
+import com.facebook.react.bridge.queue.MessageQueueThreadSpec
+import com.facebook.react.bridge.queue.ReactQueueConfiguration
+import com.facebook.react.bridge.queue.ReactQueueConfigurationImpl
+import com.facebook.react.bridge.queue.ReactQueueConfigurationSpec
+import com.facebook.react.uimanager.UIManagerModule
+import org.mockito.Mockito.mock
+import org.mockito.Mockito.`when` as whenever
+import org.robolectric.RuntimeEnvironment
+
+/** Utility for creating pre-configured instances of core react components for tests. */
+object ReactTestHelper {
+  /**
+   * @return a ReactApplicationContext that has a CatalystInstance mock returned by
+   *   [createMockCatalystInstance]
+   */
+  @JvmStatic
+  fun createCatalystContextForTest(): ReactApplicationContext =
+      ReactApplicationContext(RuntimeEnvironment.application).apply {
+        initializeWithInstance(createMockCatalystInstance())
+      }
+
+  /** @return a CatalystInstance mock that has a default working ReactQueueConfiguration. */
+  @JvmStatic
+  fun createMockCatalystInstance(): CatalystInstance {
+    val spec: ReactQueueConfigurationSpec =
+        ReactQueueConfigurationSpec.builder()
+            .setJSQueueThreadSpec(MessageQueueThreadSpec.mainThreadSpec())
+            .setNativeModulesQueueThreadSpec(MessageQueueThreadSpec.mainThreadSpec())
+            .build()
+    val reactQueueConfiguration: ReactQueueConfiguration =
+        ReactQueueConfigurationImpl.create(spec) { e -> throw RuntimeException(e) }
+    val reactInstance: CatalystInstance = mock(CatalystInstance::class.java)
+    whenever(reactInstance.getReactQueueConfiguration()).thenReturn(reactQueueConfiguration)
+    whenever(reactInstance.getNativeModule(UIManagerModule::class.java))
+        .thenReturn(mock(UIManagerModule::class.java))
+    whenever(reactInstance.isDestroyed()).thenReturn(false)
+    return reactInstance
+  }
+}