1 files changed, 39 insertions, 4 deletions

diff --git a/cli-tests/group/driver.cxx b/cli-tests/group/driver.cxx
index 68f6107..9a3c710 100644
--- a/cli-tests/group/driver.cxx
+++ b/cli-tests/group/driver.cxx
@@ -5,10 +5,14 @@
 // Test group_scanner.
 //
 
+#include <string>
 #include <iostream>
 
 #include "test.hxx"
 
+#undef NDEBUG
+#include <cassert>
+
 using namespace std;
 
 int
@@ -25,27 +29,58 @@ main (int argc, char* argv[])
     //
     string m (argv[1]);
 
+    bool sa (m.find ('s') != string::npos);
+    bool sg (m.find ('g') != string::npos);
+
     argv_scanner as (--argc, ++argv);
     group_scanner s (as);
 
+    // Verify previous two args are still valid for good measure.
+    //
+    const char* prev_a (0);
+    string prev_s;
+
+    // Verify position.
+    //
+    size_t pos (0); // argv_scanner starts from 1.
+
     while (s.more ())
     {
-      if (m.find ('s') == string::npos)
+      assert (pos < s.position ());
+      pos = s.position ();
+
+      s.peek ();
+      assert (pos == s.position ());
+
+      const char* a (0);
+      if (!sa)
       {
-        const char* a (s.next ());
+        a = s.next ();
         cout << "'" << a << "'";
       }
       else
         s.skip ();
 
-      if (m.find ('g') == string::npos)
+      if (!sg)
       {
         scanner& gs (s.group ());
         while (gs.more ())
           cout << " '" << gs.next () << "'";
       }
 
-      cout << endl;
+      if (!sa || !sg)
+        cout << endl;
+
+      if (!sa && !sg)
+      {
+        s.more ();
+
+        if (prev_a != 0)
+          assert (prev_a == prev_s);
+
+        prev_a = a;
+        prev_s = a;
+      }
     }
 
     return 0;