Merge "Add ContextUtils"

staticlibs/testutils/devicetests/com/android/testutils/ContextUtils.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+@file:JvmName("ContextUtils")
+
+package com.android.testutils
+
+import android.content.Context
+import android.os.UserHandle
+import org.mockito.AdditionalAnswers.delegatesTo
+import org.mockito.ArgumentMatchers.any
+import org.mockito.ArgumentMatchers.anyInt
+import org.mockito.Mockito.doAnswer
+import org.mockito.Mockito.doReturn
+import org.mockito.Mockito.mock
+import java.util.function.BiConsumer
+
+// Helper function so that Java doesn't have to pass a method that returns Unit
+fun mockContextAsUser(context: Context, functor: BiConsumer<Context, UserHandle>? = null) =
+    mockContextAsUser(context) { c, h -> functor?.accept(c, h) }
+
+/**
+ * Return a context with assigned user and delegate to original context.
+ *
+ * @param context the mock context to set up createContextAsUser on. After this function
+ *                is called, client code can call createContextAsUser and expect a context that
+ *                will return the correct user and userId.
+ *
+ * @param functor additional code to run on the created context-as-user instances, for example to
+ *                set up further mocks on these contexts.
+ */
+fun mockContextAsUser(context: Context, functor: ((Context, UserHandle) -> Unit)? = null) {
+    doAnswer { invocation ->
+        val asUserContext = mock(Context::class.java, delegatesTo<Context>(context))
+        val user = invocation.arguments[0] as UserHandle
+        val userId = user.identifier
+        doReturn(user).`when`(asUserContext).user
+        doReturn(userId).`when`(asUserContext).userId
+        functor?.let { it(asUserContext, user) }
+        asUserContext
+    }.`when`(context).createContextAsUser(any(UserHandle::class.java), anyInt() /* flags */)
+}