Build conditions with DSL evaluated tests:

In Condition:

  * Modify constructor to accepts tests and a default return value;
  * Implement #met?;
  * Modify #! so that it return the negated value returned by #met?.

  In Condition::DSL:

  * Modify .evaluate to build the condition with tests and the value
    returned by a the evaluated condition block.

  Add a basic Test base class, with env and arguments as attributes.

  Add some spec helpers to build some easily testable kind of Test
instances (as test doubles).

spec/support/tests_helpers.rb

@@ -0,0 +1,9 @@
+module TestsHelpers
+  def test_ok
+    double('test', success?: true)
+  end
+
+  def test_ko
+    double('test', success?: false)
+  end
+end