Add AT to ensure 0-miner Clique/IBFT are valid (#1525)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

acceptance-tests/src/test/java/tech/pegasys/pantheon/tests/acceptance/clique/CliqueZeroValidators.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2019 ConsenSys AG.
+ *
+ * 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 tech.pegasys.pantheon.tests.acceptance.clique;
+
+import tech.pegasys.pantheon.tests.acceptance.dsl.AcceptanceTestBase;
+import tech.pegasys.pantheon.tests.acceptance.dsl.node.PantheonNode;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+public class CliqueZeroValidators extends AcceptanceTestBase {
+
+  @Test
+  public void zeroValidatorsFormValidCluster() throws IOException {
+    final String[] signers = {};
+    final PantheonNode node1 = pantheon.createCliqueNodeWithValidators("node1", signers);
+    final PantheonNode node2 = pantheon.createCliqueNodeWithValidators("node2", signers);
+
+    cluster.start(node1, node2);
+
+    cluster.verify(net.awaitPeerCount(1));
+  }
+}

acceptance-tests/src/test/java/tech/pegasys/pantheon/tests/acceptance/ibft2/Ibft2ZeroValidators.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2019 ConsenSys AG.
+ *
+ * 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 tech.pegasys.pantheon.tests.acceptance.ibft2;
+
+import tech.pegasys.pantheon.tests.acceptance.dsl.AcceptanceTestBase;
+import tech.pegasys.pantheon.tests.acceptance.dsl.node.PantheonNode;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+public class Ibft2ZeroValidators extends AcceptanceTestBase {
+
+  @Test
+  public void zeroValidatorsFormValidCluster() throws IOException {
+    final String[] validators = {};
+    final PantheonNode node1 = pantheon.createIbft2NodeWithValidators("node1", validators);
+    final PantheonNode node2 = pantheon.createIbft2NodeWithValidators("node2", validators);
+
+    cluster.start(node1, node2);
+
+    cluster.verify(net.awaitPeerCount(1));
+  }
+}