Added test Issue1528#testSubCommandAliasModification

src/test/java/picocli/Issue1528.java

@@ -0,0 +1,54 @@
+package picocli;
+
+import java.util.concurrent.Callable;
+import org.junit.Test;
+import picocli.CommandLine.Command;
+import picocli.CommandLine.Model.CommandSpec;
+
+import static org.junit.Assert.assertEquals;
+
+public class Issue1528 {
+
+    @Command(name = "main", subcommands = SubCommand.class)
+    static class MainCommand implements Callable<Integer> {
+        @Override
+        public Integer call() throws Exception {
+            return null;
+        }
+    }
+
+    @Command(name = "sub")
+    static class SubCommand implements Callable<Integer> {
+        @Override
+        public Integer call() throws Exception {
+            return null;
+        }
+    }
+
+    @Test
+    public void testSubCommandAliasModification() {
+        CommandSpec cs = new CommandLine(new MainCommand()).getSubcommands().get("sub").getCommandSpec();
+
+        assertEquals(0, cs.aliases().length);
+
+        cs.aliases("alias");
+        assertEquals(1, cs.aliases().length);
+        assertEquals("alias", cs.aliases()[0]);
+
+        cs.aliases("alias", "2");
+        assertEquals(2, cs.aliases().length);
+        assertEquals("alias", cs.aliases()[0]);
+        assertEquals("2", cs.aliases()[1]);
+
+        cs.aliases("2");
+        assertEquals(1, cs.aliases().length);
+        assertEquals("2", cs.aliases()[0]);
+
+        cs.aliases("3");
+        assertEquals(1, cs.aliases().length);
+        assertEquals("3", cs.aliases()[0]);
+
+        cs.aliases(new String[0]);
+        assertEquals(0, cs.aliases().length);
+    }
+}