Implement returning multiple values

src/spectator/mocks/multi_value_method_stub.cr

@@ -0,0 +1,19 @@
+require "./generic_arguments"
+require "./generic_method_stub"
+
+module Spectator::Mocks
+  class MultiValueMethodStub(ReturnType) < GenericMethodStub(ReturnType)
+    @index = 0
+
+    def initialize(name, source, @values : ReturnType, args = nil)
+      super(name, source, args)
+      raise ArgumentError.new("Values must have at least one item") if @values.size < 1
+    end
+
+    def call(_args : GenericArguments(T2, NT2), rt : RT.class) forall T2, NT2, RT
+      value = @values[@index]
+      @index += 1 if @index < @values.size - 1
+      value
+    end
+  end
+end

src/spectator/mocks/nil_method_stub.cr

@@ -8,10 +8,18 @@ module Spectator::Mocks
       nil
     end
 
+    def and_return
+      self
+    end
+
     def and_return(value)
       ValueMethodStub.new(@name, @source, value, @args)
     end
 
+    def and_return(*values)
+      MultiValueMethodStub.new(@name, @source, values.to_a, @args)
+    end
+
     def with(*args : *T, **opts : **NT) forall T, NT
       args = GenericArguments.new(args, opts)
       NilMethodStub.new(@name, @source, args)