diff --git a/spec/unit/defines/concat_spec.rb b/spec/unit/defines/concat_spec.rb
index 7682cdf..3ace38c 100644
--- a/spec/unit/defines/concat_spec.rb
+++ b/spec/unit/defines/concat_spec.rb
@@ -19,6 +19,7 @@ describe 'concat', :type => :define do
       :replace        => true,
       :order          => 'alpha',
       :ensure_newline => false,
+      :validate_cmd   => nil,
     }.merge(params)
 
     safe_name            = title.gsub('/', '_')
@@ -76,15 +77,16 @@ describe 'concat', :type => :define do
 
       it do
         should contain_file(title).with(file_defaults.merge({
-          :ensure  => 'present',
-          :owner   => p[:owner],
-          :group   => p[:group],
-          :mode    => p[:mode],
-          :replace => p[:replace],
-          :path    => p[:path],
-          :alias   => "concat_#{title}",
-          :source  => "#{fragdir}/#{concat_name}",
-          :backup  => p[:backup],
+          :ensure       => 'present',
+          :owner        => p[:owner],
+          :group        => p[:group],
+          :mode         => p[:mode],
+          :replace      => p[:replace],
+          :path         => p[:path],
+          :alias        => "concat_#{title}",
+          :source       => "#{fragdir}/#{concat_name}",
+          :validate_cmd => p[:validate_cmd],
+          :backup       => p[:backup],
         }))
       end
 
@@ -380,6 +382,22 @@ describe 'concat', :type => :define do
     end
   end # ensure_newline =>
 
+  context 'validate_cmd =>' do
+    context '/usr/bin/test -e %' do
+      it_behaves_like 'concat', '/etc/foo.bar', { :validate_cmd => '/usr/bin/test -e %' }
+    end
+
+    [ 1234, true ].each do |cmd|
+      context cmd do
+        let(:title) { '/etc/foo.bar' }
+        let(:params) {{ :validate_cmd => cmd }}
+        it 'should fail' do
+          expect { should }.to raise_error(Puppet::Error, /\$validate_cmd must be a string/)
+        end
+      end
+    end
+  end # validate_cmd =>
+
   describe 'deprecated parameter' do
     context 'gnu =>' do
       context 'foo' do