Add some docs

src/spectator/context.cr

@@ -4,5 +4,9 @@ module Spectator
   # Base class that all test cases run in.
   # This type is used to store all test case contexts as a single type.
   # The instance must be downcast to the correct type before calling a context method.
+  #
+  # Nested contexts, such as those defined by `context` and `describe` in the DSL, can define their own methods.
+  # The intent is that a proc will downcast to the correct type and call one of those methods.
+  # This is how methods that contain test cases, hooks, and other context-specific code blocks get invoked.
   alias Context = ::SpectatorContext
 end

src/spectator/dsl/builder.cr

@@ -1,19 +1,35 @@
 require "../spec/builder"
 
 module Spectator::DSL
+  # Incrementally builds up a test spec from the DSL.
+  # This is intended to be used only by the Spectator DSL.
   module Builder
     extend self
 
+    # Underlying spec builder.
     @@builder = Spec::Builder.new
 
+    # Defines a new example group and pushes it onto the group stack.
+    # Examples and groups defined after calling this method will be nested under the new group.
+    # The group will be finished and popped off the stack when `#end_example` is called.
+    #
+    # See `Spec::Builder#start_group` for usage details.
     def start_group(*args)
       @@builder.start_group(*args)
     end
 
+    # Completes a previously defined example group and pops it off the group stack.
+    # Be sure to call `#start_group` and `#end_group` symmetically.
+    #
+    # See `Spec::Builder#end_group` for usage details.
     def end_group(*args)
       @@builder.end_group(*args)
     end
 
+    # Defines a new example.
+    # The example is added to the group currently on the top of the stack.
+    #
+    # See `Spec::Builder#add_example` for usage details.
     def add_example(*args, &block : Example, Context ->)
       @@builder.add_example(*args, &block)
     end

src/spectator/spec/builder.cr

@@ -3,6 +3,10 @@ require "../example_context_method"
 require "../example_group"
 
 module Spectator
+  # Progressively builds a test spec.
+  #
+  # A stack is used to track the current example group.
+  # Adding an example or group will nest it under the group at the top of the stack.
   class Spec::Builder
     # Stack tracking the current group.
     # The bottom of the stack (first element) is the root group.
@@ -11,16 +15,26 @@ module Spectator
     # New examples should be added to the current group.
     @group_stack : Deque(ExampleGroup)
 
+    # Creates a new spec builder.
+    # A root group is pushed onto the group stack.
     def initialize
       root_group = ExampleGroup.new
       @group_stack = Deque(ExampleGroup).new
       @group_stack.push(root_group)
     end
 
-    def add_example
-      raise NotImplementedError.new("#add_example")
-    end
-
+    # Defines a new example group and pushes it onto the group stack.
+    # Examples and groups defined after calling this method will be nested under the new group.
+    # The group will be finished and popped off the stack when `#end_example` is called.
+    #
+    # The *name* is the name or brief description of the group.
+    # This should be a symbol when describing a type - the type name is represented as a symbol.
+    # Otherwise, a string should be used.
+    #
+    # The *source* optionally defined where the group originates in source code.
+    #
+    # The newly created group is returned.
+    # It shouldn't be used outside of this class until a matching `#end_group` is called.
     def start_group(name, source = nil) : ExampleGroup
       {% if flag?(:spectator_debug) %}
         puts "Start group: #{name.inspect} @ #{source}"
@@ -30,7 +44,13 @@ module Spectator
       end
     end
 
-    def end_group
+    # Completes a previously defined example group and pops it off the group stack.
+    # Be sure to call `#start_group` and `#end_group` symmetically.
+    #
+    # The completed group will be returned.
+    # At this point, it is safe to use the group.
+    # All of its examples and sub-groups have been populated.
+    def end_group : ExampleGroup
       {% if flag?(:spectator_debug) %}
         puts "End group: #{current_group}"
       {% end %}
@@ -39,7 +59,25 @@ module Spectator
       @group_stack.pop
     end
 
-    def add_example(name, source, context, &block : Example, Context ->)
+    # Defines a new example.
+    # The example is added to the group currently on the top of the stack.
+    #
+    # The *name* is the name or brief description of the example.
+    # This should be a string or nil.
+    # When nil, the example's name will be populated by the first expectation run inside of the test code.
+    #
+    # The *source* optionally defined where the example originates in source code.
+    #
+    # The *context* is an instance of the context the test code should run in.
+    # See `Context` for more information.
+    #
+    # A block must be provided.
+    # It will be yielded two arguments - the example created by this method, and the *context* argument.
+    # The return value of the block is ignored.
+    # It is expected that the test code runs when the block is called.
+    #
+    # The newly created example is returned.
+    def add_example(name, source, context, &block : Example, Context ->) : Example
       {% if flag?(:spectator_debug) %}
         puts "Add example: #{name} @ #{source}"
       {% end %}
@@ -48,7 +86,12 @@ module Spectator
       # The example is added to the current group by `Example` initializer.
     end
 
-    def build
+    # Constructs the test spec.
+    # Returns the spec instance.
+    #
+    # Raises an error if there were not symmetrical calls to `#start_group` and `#end_group`.
+    # This would indicate a logical error somewhere in Spectator or an extension of it.
+    def build : Spec
       raise NotImplementedError.new("#build")
     end
 
@@ -62,7 +105,7 @@ module Spectator
       @group_stack.first
     end
 
-    # Retrieves the current group.
+    # Retrieves the current group, which is at the top of the stack.
     # This is the group that new examples should be added to.
     private def current_group
       @group_stack.last