Implemented should-syntax

README.md

@@ -93,7 +93,7 @@ In no particular order, features that have been implemented and are planned:
     - [X] Before and after hooks - `before_each`, `before_all`, `after_each`, `after_all`, `around_each`
     - [ ] Other hooks - `on_success`, `on_failure`, `on_error`
     - [ ] One-liner syntax
-    - [ ] Should syntax
+    - [X] Should syntax - `should`, `should_not`
     - [X] Helper methods and modules
     - [ ] Aliasing - custom example group types with preset attributes
     - [X] Pending tests - `pending`

src/spectator/should.cr

@@ -0,0 +1,37 @@
+class Object
+  # Extension method to create an expectation for an object.
+  # This is part of the spec DSL and mimics Crystal Spec's default should-syntax.
+  # A matcher should immediately follow this method, or be the only argument to it.
+  # Example usage:
+  # ```
+  # it "equals the expected value" do
+  #   subject.should eq(42)
+  # end
+  # ```
+  #
+  # NOTE: By default, the should-syntax is disabled.
+  # The expect-syntax is preferred,
+  # since it doesn't [monkey-patch](https://en.wikipedia.org/wiki/Monkey_patch) all objects.
+  # To enable should-syntax, add the following to your `spec_helper.cr` file:
+  # ```
+  # require "spectator/should"
+  # ```
+  def should(matcher : ::Spectator::Matchers::Matcher)
+    # First argument of the `Expectation` initializer is the expression label.
+    # However, since this isn't a macro and we can't "look behind" this method call
+    # to see what it was invoked on, the argument is an empty string.
+    expectation = ::Spectator::Expectation.new("", self)
+    unless matcher.match?(expectation)
+      raise ::Spectator::ExpectationFailed.new(matcher.message(expectation))
+    end
+  end
+
+  # Works the same as `#should` except the condition is inverted.
+  # When `#should` succeeds, this method will fail, and vice-versa.
+  def should_not(matcher : ::Spectator::Matchers::Matcher)
+    expectation = ::Spectator::Expectation.new("", self)
+    if matcher.match?(expectation)
+      raise ::Spectator::ExpectationFailed.new(matcher.message(expectation))
+    end
+  end
+end