--- /dev/null
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Verification if it's possible to define a simple expects contract.
+
+class MyClass
+ fun foo(x: Int)
+ is
+ expects(x > 0)
+ do
+ if x <= 0 then print "FAIL"
+ end
+end
+
+class MyClass2
+ fun foo(bool: Bool)
+ is
+ expects(not bool)
+ do
+ if bool then print "FAIL"
+ end
+end
+
+var first = new MyClass
+first.foo(1) # OK
+var second = new MyClass2
+second.foo(false) # OK