Some initial work on examples and groups

src/core/example.cr

@@ -0,0 +1,29 @@
+module Spectator
+  # Information about a test case and functionality for running it.
+  class Example
+    # Name of the example.
+    # This may be nil if the example does not have a name.
+    # In that case, the description of the first matcher executed in the example should be used.
+    property! name : String
+
+    # Creates a new example.
+    # The *name* may be nil if the example has no name.
+    def initialize(@name = nil, &@block : Example -> Nil)
+    end
+
+    # Runs the example.
+    def run
+      @block.call(self)
+    end
+
+    # Constructs a string representation of the example.
+    # The name will be used if it is set, otherwise the example will be anonymous.
+    def to_s(io : IO) : Nil
+      if (name = @name)
+        io << name
+      else
+        io << "<Anonymous Example>"
+      end
+    end
+  end
+end

src/core/example_group.cr

@@ -0,0 +1,26 @@
+module Spectator
+  # Information about a group of examples and functionality for running them.
+  # The group can be nested.
+  class ExampleGroup
+    # Name of the group.
+    # This may be nil if the group does not have a name.
+    property! name : String
+
+    getter examples = [] of Example
+
+    # Creates a new group.
+    # The *name* may be nil if the group has no name.
+    def initialize(@name = nil)
+    end
+
+    # Constructs a string representation of the group.
+    # The name will be used if it is set, otherwise the group will be anonymous.
+    def to_s(io : IO) : Nil
+      if (name = @name)
+        io << name
+      else
+        io << "<Anonymous Context>"
+      end
+    end
+  end
+end