Introduce UserId utility class

pgpainless-core/src/test/java/org/pgpainless/key/UserIdTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2020 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 org.pgpainless.key;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.pgpainless.key.util.UserId;
+
+public class UserIdTest {
+
+    @Test(expected = IllegalArgumentException.class)
+    public void throwForNullName() {
+        UserId.withName(null);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void throwForNullComment() {
+        UserId.withName("foo")
+                .withComment(null);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void throwForNullEmail() {
+        UserId.withName("foo")
+                .withComment("bar")
+                .withEmail(null);
+    }
+
+    @Test
+    public void testFormatOnlyName() {
+        assertEquals(
+                "Juliet Capulet",
+                UserId.withName("Juliet Capulet")
+                        .build().toString());
+    }
+
+    @Test
+    public void testFormatNameAndComment() {
+        assertEquals(
+                "Juliet Capulet (from the play)",
+                UserId.withName("Juliet Capulet")
+                        .withComment("from the play")
+                        .noEmail().toString());
+    }
+
+    @Test
+    public void testFormatNameCommentAndMail() {
+        assertEquals("Juliet Capulet (from the play) <juliet@capulet.lit>",
+                UserId.withName("Juliet Capulet")
+                        .withComment("from the play")
+                        .withEmail("juliet@capulet.lit")
+                        .toString());
+    }
+
+    @Test
+    public void testFormatNameAndEmail() {
+        assertEquals("Juliet Capulet <juliet@capulet.lit>",
+                UserId.withName("Juliet Capulet")
+                        .noComment()
+                        .withEmail("juliet@capulet.lit")
+                        .toString());
+    }
+}