Base PGPainlessCLI on new sop-java module

* Rename pgpainless-sop -> pgpainless-cli
* Introduce sop-java (implementation-independent SOP API)
* Introduce sop-java-picocli (CLI frontend for sop-java)
* Introduce pgpainless-sop (implementation of sop-java using PGPainless)
* Rework pgpainless-cli (plugs pgpainless-sop into sop-java-picocli)

sop-java/src/test/java/sop/util/ReadyWithResultTest.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2021 Paul Schaub.
+ *
+ * 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 sop.util;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import sop.ByteArrayAndResult;
+import sop.ReadyWithResult;
+import sop.Verification;
+import sop.exception.SOPGPException;
+
+public class ReadyWithResultTest {
+
+    @Test
+    public void testReadyWithResult() throws SOPGPException.NoSignature, IOException {
+        byte[] data = "Hello, World!\n".getBytes(StandardCharsets.UTF_8);
+        List<Verification> result = Collections.singletonList(
+                new Verification(UTCUtil.parseUTCDate("2019-10-24T23:48:29Z"),
+                        "C90E6D36200A1B922A1509E77618196529AE5FF8",
+                        "C4BC2DDB38CCE96485EBE9C2F20691179038E5C6")
+        );
+        ReadyWithResult<List<Verification>> readyWithResult = new ReadyWithResult<List<Verification>>() {
+            @Override
+            public List<Verification> writeTo(OutputStream outputStream) throws IOException, SOPGPException.NoSignature {
+                outputStream.write(data);
+                return result;
+            }
+        };
+
+        ByteArrayAndResult<List<Verification>> bytesAndResult = readyWithResult.toBytes();
+        assertArrayEquals(data, bytesAndResult.getBytes());
+        assertEquals(result, bytesAndResult.getResult());
+    }
+}