Add some RSpec docs tests for hooks

spec/rspec/core/before_and_after_hooks_spec.cr

@@ -0,0 +1,113 @@
+require "../../spec_helper"
+
+# Examples taken from:
+# https://relishapp.com/rspec/rspec-core/v/3-8/docs/hooks/before-and-after-hooks
+# and modified to fit Spectator and Crystal.
+Spectator.describe "`before` and `after` hooks" do
+  context "Define `before_each` block" do
+    class Thing
+      def widgets
+        @widgets ||= [] of Symbol # Must specify array element type.
+      end
+    end
+
+    describe Thing do
+      before_each do
+        @thing = Thing.new
+      end
+
+      describe "initialize in before_each" do
+        it "has 0 widgets" do
+          widgets = @thing.as(Thing).widgets # Must cast since compile type is Thing?
+          expect(widgets.size).to eq(0) # Use size instead of count.
+        end
+
+        it "can accept new widgets" do
+          widgets = @thing.as(Thing).widgets # Must cast since compile type is Thing?
+          widgets << :foo
+        end
+
+        it "does not share state across examples" do
+          widgets = @thing.as(Thing).widgets  # Must cast since compile type is Thing?
+          expect(widgets.size).to eq(0) # Use size instead of count.
+        end
+      end
+    end
+  end
+
+  context "Define `before_all` block in example group" do
+    class Thing
+      def widgets
+        @widgets ||= [] of Symbol # Must specify array element type.
+      end
+    end
+
+    describe Thing do
+      # Moved before_all into the same example group.
+      # Unlike Ruby, inherited class variables don't share the same value.
+      # See: https://crystal-lang.org/reference/syntax_and_semantics/class_variables.html
+      describe "initialized in before_all" do
+        @@thing : Thing?
+
+        before_all do
+          @@thing = Thing.new # Must use class variables.
+        end
+
+        it "has 0 widgets" do
+          widgets = @@thing.as(Thing).widgets # Must cast since compile type is Thing?
+          expect(widgets.size).to eq(0) # Use size instead of count.
+        end
+
+        it "can accept new widgets" do
+          widgets = @@thing.as(Thing).widgets # Must cast since compile type is Thing?
+          widgets << :foo
+        end
+
+        it "shares state across examples" do
+          widgets = @@thing.as(Thing).widgets  # Must cast since compile type is Thing?
+          expect(widgets.size).to eq(1) # Use size instead of count.
+        end
+      end
+    end
+  end
+
+  context "Failure in `before_each` block" do
+    # TODO
+  end
+
+  context "Failure in `after_each` block" do
+    # TODO
+  end
+
+  context "Define `before` and `after` blocks in configuration" do
+    # TODO
+  end
+
+  context "`before`/`after` blocks are run in order" do
+    # Examples changed from using puts to appending to an array.
+    describe "before and after callbacks" do
+      @@order = [] of Symbol
+
+      before_all do
+        @@order << :before_all
+      end
+
+      before_each do
+        @@order << :before_each
+      end
+
+      after_each do
+        @@order << :after_each
+      end
+
+      after_all do
+        @@order << :after_all
+      end
+
+      xit "gets run in order" do
+        # TODO: The after_all hook isn't evaluated yet because the group hasn't "finished."
+        expect(@@order).to_eventually eq(%i[before_all before_each after_each after_all])
+      end
+    end
+  end
+end