Implement tasks condition feature

features/condition.feature

@@ -0,0 +1,15 @@
+Feature: condition
+
+  Scenario: prevents task evaluation when condition is not met
+    Given a recipe with:
+      """
+      task :hello do
+        condition { false }
+
+        puts 'evaluated'
+        exit 70
+      end
+      """
+    When I execute the recipe
+    Then the exit status must be 0
+    And the output must not contain "evaluated"