zzz 961 initial values for arggroups

Index: src/test/java/picocli/ArgGroupTest.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/test/java/picocli/ArgGroupTest.java	(date 1587356173923)
+++ src/test/java/picocli/ArgGroupTest.java	(date 1587356173923)
@@ -2366,6 +2366,9 @@
             @Option(names = "--l1b", required = true)
             private String l1b;
 
+            @Option(names = "--l1c")
+            private String l1c = "111";
+
             @ArgGroup(exclusive = false, multiplicity = "1")
             private Level2Argument level2;
         }
@@ -2373,9 +2376,13 @@
         static class Level2Argument {
             @Option(names = "--l2a", required = true, defaultValue = "l2a")
             private String l2a;
+
             @Option(names = "--l2b", required = true)
             private String l2b;
 
+            @Option(names = "--l2c")
+            private String l2c = "222";
+
             @ArgGroup(exclusive = false, multiplicity = "1")
             private Level3Argument level3;
         }
@@ -2386,6 +2393,9 @@
 
             @Option(names = { "--l3b"}, required = true, defaultValue = "l3b")
             private String l3b;
+
+            @Option(names = "--l3c")
+            private String l3c = "333";
         }
 
         @Command(name = "arg-group-test", subcommands = {CreateCommand.class, CommandLine.HelpCommand.class})
@@ -2395,8 +2405,11 @@
 
         @Command(name = "create", helpCommand = true)
         public static class CreateCommand implements Runnable {
-            @Option(names = "--l0", required = true, defaultValue = "l0")
-            private String l0;
+            @Option(names = "--l0a", required = true, defaultValue = "l0")
+            private String l0a;
+
+            @Option(names = "--l0b")
+            private String l0b = "000";
 
             @ArgGroup(exclusive = false, multiplicity = "0..1")
             private Level1Argument level1 = new Level1Argument();
@@ -2405,15 +2418,27 @@
         }
     }
 
+    @Test
+    public void testRequiredOptionsNotMandatoryIfInitialValueIsSpecified() {
+        CommandLine cmd = new CommandLine(new Issue746.Level3Argument());
+        cmd.parseArgs("--l3a=L3A");
+        Issue746.Level3Argument bean = cmd.getCommand();
+        assertEquals("L3A", bean.l3a);
+        assertEquals("l3b", bean.l3b);
+        assertEquals("333", bean.l3c);
+    }
+
     @Test
     // https://github.com/remkop/picocli/issues/746
     public void testIssue746DefaultValueWithNestedArgGroups() {
         Issue746.CreateCommand bean = new Issue746.CreateCommand();
         CommandLine cmd = new CommandLine(bean);
         cmd.parseArgs();
-        assertEquals("l0", bean.l0);
+        assertEquals("l0", bean.l0a);
+        assertEquals("000", bean.l0b);
         assertEquals("l1a", bean.level1.l1a);
         assertNull(bean.level1.l1b);
+        assertEquals("111", bean.level1.l1c);
         assertNull(bean.level1.level2);
     }
 
@@ -2421,8 +2446,9 @@
     // https://github.com/remkop/picocli/issues/746
     public void testIssue746ArgGroupWithDefaultValuesSynopsis() {
         String expected = String.format("" +
-                "create [[--l1a=<l1a>] --l1b=<l1b> ([--l2a=<l2a>] --l2b=<l2b> (--l3a=<l3a>%n" +
-                "       [--l3b=<l3b>]))] [--l0=<l0>]%n");
+                "create [[--l1a=<l1a>] --l1b=<l1b> [--l1c=<l1c>] ([--l2a=<l2a>] --l2b=<l2b>%n" +
+                "       [--l2c=<l2c>] (--l3a=<l3a> [--l3b=<l3b>] [--l3c=<l3c>]))] [--l0a=<l0a>]%n" +
+                "       [--l0b=<l0b>]%n");
 
         CommandLine cmd = new CommandLine(new Issue746.CreateCommand());
         Help help = new Help(cmd.getCommandSpec(), Help.defaultColorScheme(Help.Ansi.OFF));
@@ -2434,20 +2460,25 @@
     @Test
     // https://github.com/remkop/picocli/issues/746
     public void testIssue746ArgGroupWithDefaultValuesParsing() {
+        //System.setProperty("picocli.trace", "DEBUG");
         Issue746.CreateCommand bean = new Issue746.CreateCommand();
         CommandLine cmd = new CommandLine(bean);
 
         cmd.parseArgs("--l1b=L1B --l2b=L2B --l3a=L3A".split(" "));
-        assertEquals("default value", "l0", bean.l0);
+        assertEquals("default value", "l0", bean.l0a);
+        assertEquals("default value", "000", bean.l0b);
         assertNotNull(bean.level1);
         assertEquals("default value", "l1a", bean.level1.l1a);
         assertEquals("specified value", "L1B", bean.level1.l1b);
+        assertEquals("initial value", "111", bean.level1.l1c);
         assertNotNull(bean.level1.level2);
         assertEquals("default value", "l2a", bean.level1.level2.l2a);
         assertEquals("specified value", "L2B", bean.level1.level2.l2b);
+        assertEquals("initial value", "222", bean.level1.level2.l2c);
         assertNotNull(bean.level1.level2.level3);
         assertEquals("default value", "l3b", bean.level1.level2.level3.l3b);
         assertEquals("specified value", "L3A", bean.level1.level2.level3.l3a);
+        assertEquals("initial value", "333", bean.level1.level2.level3.l3c);
     }
 
     @Command(name = "Issue742")