Assertion helpers

doc/misc.adoc

@@ -356,3 +356,54 @@ let err, val = trying({
 The error is the left value, the correct one the right (mnemonic: “right” also means “correct”). This allows to deal with error in the same way as Go does for instance.
 
 The decorators `nullify` and `raising` are the duals of `option` or `result`
+
+=== Assertions (`gololang.Assertions`)
+
+It allows to declare (and test) an expected boolean condition in a program.
+
+==== `assert`
+
+Ensure that a boolean expression is true at runtime:
+
+[source,golo]
+----
+assert(-> 5: equals(5))
+
+# If you don't provide callback to assert(), an AssertionError is thrown if the predicate is false
+assert(-> 5: equals(42))
+
+assert(-> "Golo" oftype Integer.class, |error| {
+  println("Huston?")
+})
+
+assert(predicate= -> 5 < 0, onSuccess=|res|{
+  println("You win!")
+}, onError=|err|{
+  println("5 is not less than 0!")
+})
+----
+
+==== `assertEqual`
+
+Ensure that two expressions are equal to each other:
+
+[source,golo]
+----
+# be careful, if no callback and assertion is false, then the program is aborted
+assertEqual(42, 42)
+
+assertEqual(42, 69, |error| {
+  println(error)
+})
+
+let point = Point(5,5)
+assertEqual(point: frozenCopy(), point: frozenCopy(), |res| { # success
+    println(":)")
+  },
+  |error| { # fail
+    println(":(")
+})
+
+# display report of results
+gololang.Assertions.displayTestsReport()
+----

samples/some-assertions.golo

@@ -0,0 +1,58 @@
+# Copyright (c) 2012-2016 Institut National des Sciences Appliquées de Lyon (INSA-Lyon)
+#
+# All rights reserved. This Example Content is intended to demonstrate
+# usage of Eclipse technology. It is provided to you under the terms and
+# conditions of the Eclipse Distribution License v1.0 which is available
+# at http://www.eclipse.org/org/documents/edl-v10.php
+
+module golo.samples.Assertions
+
+import gololang.Assertions
+
+struct Point = {
+  x, y
+}
+
+function main = |args| {
+
+  assert(-> 5: equals(5))
+
+  assert(-> "BoB" oftype String.class, |error| {
+    println("Huston?")
+  })
+
+  assert(predicate= -> "BoB" oftype Integer.class,
+    successMessage= "This is an Integer",
+    onSuccess= |res| {
+      println("You Win")
+    },
+    errorMessage= "This isn't an Integer",
+    onError = |error| {
+      println("Huston?")
+    }
+  )
+
+  assert(predicate= -> 5 < 0, onSuccess=|res| {}, onError=|err| {
+    println("5 is not less than 0!")
+  })
+
+  assertEqual(42, 42)
+
+  assertEqual(42, 69, |error| {
+    println(error)
+  })
+
+  assertEqual(Point(5,5), Point(5,5), |error| {
+    println("???")
+  })
+
+  let point = Point(5,5)
+  assertEqual(point: frozenCopy(), point: frozenCopy(), |res| {
+      println(":)")
+    },
+    |error| {
+      println(":(")
+  })
+
+  gololang.Assertions.displayTestsReport()
+}