1 files changed, 44 insertions, 0 deletions
diff --git a/notification/Bubbles/app/src/test/java/com/example/android/bubbles/LiveDataTestUtils.kt b/notification/Bubbles/app/src/test/java/com/example/android/bubbles/LiveDataTestUtils.kt
new file mode 100644
index 00000000..6c74bb36
--- /dev/null
+++ b/notification/Bubbles/app/src/test/java/com/example/android/bubbles/LiveDataTestUtils.kt
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2019 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.example.android.bubbles
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Observer
+import androidx.test.platform.app.InstrumentationRegistry
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+
+/**
+ * Observes this [LiveData] and returns the value.
+ *
+ * @throws NullPointerException if the observed value is null.
+ */
+fun <T> LiveData<T>.observedValue(): T {
+    var result: T? = null
+    val latch = CountDownLatch(1)
+    val observer = Observer<T> {
+        result = it
+        latch.countDown()
+    }
+    InstrumentationRegistry.getInstrumentation().runOnMainSync {
+        observeForever(observer)
+    }
+    latch.await(3000L, TimeUnit.MILLISECONDS)
+    InstrumentationRegistry.getInstrumentation().runOnMainSync {
+        removeObserver(observer)
+    }
+    return result!!
+}