[PM-21328] Migrate BaseViewModelTest and MainDispatcherExtension to test fixtures (#5146)

ui/src/testFixtures/kotlin/com/bitwarden/ui/platform/base/BaseViewModelTest.kt

@@ -0,0 +1,28 @@
+package com.bitwarden.ui.platform.base
+
+import app.cash.turbine.ReceiveTurbine
+import app.cash.turbine.TurbineContext
+import app.cash.turbine.turbineScope
+import kotlinx.coroutines.CoroutineScope
+import org.junit.jupiter.api.extension.RegisterExtension
+
+abstract class BaseViewModelTest {
+    @Suppress("unused", "JUnitMalformedDeclaration")
+    @RegisterExtension
+    protected open val mainDispatcherExtension = MainDispatcherExtension()
+
+    protected suspend fun <S : Any, E : Any, T : BaseViewModel<S, E, *>> T.stateEventFlow(
+        backgroundScope: CoroutineScope,
+        validate: suspend TurbineContext.(
+            stateFlow: ReceiveTurbine<S>,
+            eventFlow: ReceiveTurbine<E>,
+        ) -> Unit,
+    ) {
+        turbineScope {
+            this.validate(
+                this@stateEventFlow.stateFlow.testIn(backgroundScope),
+                this@stateEventFlow.eventFlow.testIn(backgroundScope),
+            )
+        }
+    }
+}

ui/src/testFixtures/kotlin/com/bitwarden/ui/platform/base/MainDispatcherExtension.kt

@@ -0,0 +1,45 @@
+package com.bitwarden.ui.platform.base
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.TestDispatcher
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+import org.junit.jupiter.api.extension.AfterAllCallback
+import org.junit.jupiter.api.extension.AfterEachCallback
+import org.junit.jupiter.api.extension.BeforeAllCallback
+import org.junit.jupiter.api.extension.BeforeEachCallback
+import org.junit.jupiter.api.extension.ExtendWith
+import org.junit.jupiter.api.extension.ExtensionContext
+import org.junit.jupiter.api.extension.RegisterExtension
+
+/**
+ * JUnit 5 Extension for automatically setting a [testDispatcher] as the "main" dispatcher.
+ *
+ * Note that this may be used as a normal class property with [RegisterExtension] or may be applied
+ * directly to a test class using [ExtendWith].
+ */
+@OptIn(ExperimentalCoroutinesApi::class)
+class MainDispatcherExtension(
+    private val testDispatcher: TestDispatcher = UnconfinedTestDispatcher(),
+) : AfterAllCallback,
+    AfterEachCallback,
+    BeforeAllCallback,
+    BeforeEachCallback {
+    override fun afterAll(context: ExtensionContext?) {
+        Dispatchers.resetMain()
+    }
+
+    override fun afterEach(context: ExtensionContext?) {
+        Dispatchers.resetMain()
+    }
+
+    override fun beforeAll(context: ExtensionContext?) {
+        Dispatchers.setMain(testDispatcher)
+    }
+
+    override fun beforeEach(context: ExtensionContext?) {
+        Dispatchers.setMain(testDispatcher)
+    }
+}