2 files changed, 39 insertions, 1 deletions
diff --git a/lib/custodian/parser.rb b/lib/custodian/parser.rb
index 7ed7a51..268dd3b 100755
--- a/lib/custodian/parser.rb
+++ b/lib/custodian/parser.rb
@@ -190,6 +190,10 @@ class MonitorConfig
 
     end
 
+    if ( is_macro?( name ) )
+      raise ArgumentError, "The macro #{name} is already defined"
+    end
+
     @MACROS[name] = val
   end
 
diff --git a/t/test-parser.rb b/t/test-parser.rb
index c3e782f..f405433 100755
--- a/t/test-parser.rb
+++ b/t/test-parser.rb
@@ -57,7 +57,6 @@ class TestParser < Test::Unit::TestCase
     assert_nothing_raised do
       MonitorConfig.new("/dev/null" )
     end
-
   end
 
 
@@ -171,6 +170,41 @@ class TestParser < Test::Unit::TestCase
 
 
 
+  #
+  # Redefinining a macro should cause an error
+  #
+  def test_duplicate_macro
+
+
+    #
+    # Create the parser.
+    #
+    parser = MonitorConfig.new("/dev/null" )
+
+
+    #
+    #  With nothing loaded we should have zero macros - so the
+    # count of our macros hash should be zero
+    #
+    macros = parser.macros
+    assert( macros.empty? )
+    assert( macros.size() == 0 )
+
+
+    #
+    #  Define a macro twice.  The first will work, the second will fail
+    #
+    assert_nothing_raised do
+      parser.define_macro( "FOO is kvm1.vm.bytemark.co.uk and kvm2.vm.bytemark.co.uk." )
+    end
+
+    assert_raise ArgumentError do
+      parser.define_macro( "FOO is kvm1.vm.bytemark.co.uk and kvm2.vm.bytemark.co.uk." )
+    end
+  end
+
+
+
 
   #
   #  Test that we can define macros with only a single host.