[#2145] add test

picocli-codegen/src/test/java/picocli/codegen/docgen/manpage/Issue2145.java

@@ -0,0 +1,24 @@
+package picocli.codegen.docgen.manpage;
+
+import org.junit.Test;
+import picocli.CommandLine;
+
+import static org.junit.Assert.*;
+
+public class Issue2145 {
+
+    @CommandLine.Command(
+        name = "documentation",
+        description = "Command to generate CLI documentation",
+        subcommands = ManPageGenerator.class
+    )
+    static class Documentation {
+
+    }
+
+    @Test
+    public void testManPageGenAsSubcommand() {
+        int result = new CommandLine(new Documentation()).execute("gen-manpage", "-dout", "-v");
+        assertEquals(0, result);
+    }
+}