diff --git a/changes.xml b/changes.xml
index 8393c67..1ff1a59 100644
--- a/changes.xml
+++ b/changes.xml
@@ -38,6 +38,12 @@
   </properties>
 
   <release version="1.2" date="not-released">
+    <action type="update" breaks-bwc="true">
+      assertResourceContains now first validates that the given
+      resource actually exists using assertResourceExists - this may
+      lead to a different error message than the ones generated with
+      AntUnit 1.1.
+    </action>
     <action type="add">
       New assertion assertResourceExists and assertResourceDoesntExist
       have been added.
diff --git a/src/main/org/apache/ant/antunit/antlib.xml b/src/main/org/apache/ant/antunit/antlib.xml
index fb167d1..932258c 100644
--- a/src/main/org/apache/ant/antunit/antlib.xml
+++ b/src/main/org/apache/ant/antunit/antlib.xml
@@ -175,6 +175,7 @@ under the License.
     <attribute name="message"
 	       default="Expected resource '@{resource}' to contain value '@{value}' but was '${@{resource}}'"/>
     <sequential>
+      <au:assertResourceExists resource="@{resource}"/>
       <au:fail message="@{message}">
 	<resourcecontains resource="@{resource}" substring="@{value}"
                           casesensitive="@{casesensitive}"/>