Create a base test class and have all unit tests extend it

This commit creates the `RxJavaTest` class defining a default
timeout to 5 minutes. An ignored test announce itself for each
running class extending it preventing Travis CI from killing the
build.

Have `Completable` tests extend from `RxJavaTest`.
Have `Disposable` tests extend from `RxJavaTest`.
Have `Exception` tests extend from `RxJavaTest`

Closes: #6583

Author: RomanWuattier

src/test/java/io/reactivex/RxJavaTest.java

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * 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 io.reactivex;
+
+import org.junit.Ignore;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Timeout;
+
+import java.util.concurrent.TimeUnit;
+
+public abstract class RxJavaTest {
+    @Rule
+    public Timeout globalTimeout = new Timeout(5, TimeUnit.MINUTES);
+
+    /**
+     * Announce creates a log print preventing Travis CI from killing the build.
+     */
+    @Test
+    @Ignore
+    public final void announce() {
+    }
+}

src/test/java/io/reactivex/completable/CompletableRetryTest.java

@@ -14,6 +14,7 @@
 package io.reactivex.completable;
 
 import io.reactivex.Completable;
+import io.reactivex.RxJavaTest;
 import io.reactivex.functions.Action;
 import io.reactivex.functions.Predicate;
 import io.reactivex.internal.functions.Functions;
@@ -22,7 +23,7 @@
 
 import static org.junit.Assert.assertEquals;
 
-public class CompletableRetryTest {
+public class CompletableRetryTest extends RxJavaTest {
     @Test
     public void retryTimesPredicateWithMatchingPredicate() {
         final AtomicInteger atomicInteger = new AtomicInteger(3);