1 files changed, 94 insertions, 0 deletions
diff --git a/tests/testables/src/android/testing/PollingCheck.java b/tests/testables/src/android/testing/PollingCheck.java
new file mode 100644
index 000000000000..5a31450f048f
--- /dev/null
+++ b/tests/testables/src/android/testing/PollingCheck.java
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2018 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 android.testing;
+
+import junit.framework.Assert;
+import java.util.concurrent.Callable;
+
+public abstract class PollingCheck {
+    private static final long TIME_SLICE = 50;
+    private long mTimeout = 3000;
+
+    public static interface PollingCheckCondition {
+        boolean canProceed();
+    }
+
+    public PollingCheck() {
+    }
+
+    public PollingCheck(long timeout) {
+        mTimeout = timeout;
+    }
+
+    protected abstract boolean check();
+
+    public void run() {
+        if (check()) {
+            return;
+        }
+
+        long timeout = mTimeout;
+        while (timeout > 0) {
+            try {
+                Thread.sleep(TIME_SLICE);
+            } catch (InterruptedException e) {
+                Assert.fail("unexpected InterruptedException");
+            }
+
+            if (check()) {
+                return;
+            }
+
+            timeout -= TIME_SLICE;
+        }
+
+        Assert.fail("unexpected timeout");
+    }
+
+    public static void check(CharSequence message, long timeout, Callable<Boolean> condition)
+            throws Exception {
+        while (timeout > 0) {
+            if (condition.call()) {
+                return;
+            }
+
+            Thread.sleep(TIME_SLICE);
+            timeout -= TIME_SLICE;
+        }
+
+        Assert.fail(message.toString());
+    }
+
+    public static void waitFor(final PollingCheckCondition condition) {
+        new PollingCheck() {
+            @Override
+            protected boolean check() {
+                return condition.canProceed();
+            }
+        }.run();
+    }
+
+    public static void waitFor(long timeout, final PollingCheckCondition condition) {
+        new PollingCheck(timeout) {
+            @Override
+            protected boolean check() {
+                return condition.canProceed();
+            }
+        }.run();
+    }
+}
+