Asserts a condition and makes the build fail (using a special kind of BuildException) if it doesn't hold true.
| Attribute | Description | Required | 
| message | Message for the exception if the condition doesn't hold true. Defaults to "Assertion failed". | No. | 
You can use all supported conditions of Ant's core as well as any class that implements the Condition interface as a nested child element. This element is required - exactly one child - and specifies the condition to assert.
Make the build fail with the message "foo is bar" if the
      property foo has the value bar:
      <assertTrue message="foo is bar">
        <not>
          <equals arg1="${foo}" arg2="bar"/>
        </not>
      </assertTrue>