mv com/google/domain/registry google/registry

This change renames directories in preparation for the great package
rename. The repository is now in a broken state because the code
itself hasn't been updated. However this should ensure that git
correctly preserves history for each file.

javatests/google/registry/testing/SystemInfo.java

@@ -0,0 +1,63 @@
+// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
+//
+// 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.google.domain.registry.testing;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.domain.registry.util.FormattingLogger;
+
+import java.io.IOException;
+import java.util.concurrent.ExecutionException;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/** Utility class for getting system information in tests. */
+@ThreadSafe
+public final class SystemInfo {
+
+  private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();
+
+  private static final LoadingCache<String, Boolean> hasCommandCache = CacheBuilder.newBuilder()
+      .build(new CacheLoader<String, Boolean>() {
+        @Override
+        public Boolean load(String cmd) throws InterruptedException {
+          try {
+            Process pid = Runtime.getRuntime().exec(cmd);
+            pid.getOutputStream().close();
+            pid.waitFor();
+          } catch (IOException e) {
+            logger.warningfmt(e, "%s command not available", cmd);
+            return false;
+          }
+          return true;
+        }});
+
+  /**
+   * Returns {@code true} if system command can be run from path.
+   *
+   * <p><b>Warning:</b> The command is actually run! So there could be side-effects. You might
+   * need to specify a version flag or something. Return code is ignored.
+   *
+   * <p>This result is a memoized. If multiple therads try to get the same result at once, the
+   * heavy lifting will only be performed by the first thread and the rest will wait.
+   *
+   * @throws ExecutionException
+   */
+  public static boolean hasCommand(String cmd) throws ExecutionException {
+    return hasCommandCache.get(cmd);
+  }
+
+}