Add support for any_args in DSL

spec/spectator/dsl/mocks/stub_spec.cr

@@ -103,4 +103,14 @@ Spectator.describe "Stub DSL", :smoke do
       end
     end
   end
+
+  describe "#any_args" do
+    it "defines a stub with no arguments constraint" do
+      allow(dbl).to receive(:foo).with(any_args).and_return(5)
+      aggregate_failures do
+        expect(dbl.foo).to eq(5)
+        expect(dbl.foo(0)).to eq(5)
+      end
+    end
+  end
 end

src/spectator/dsl/mocks.cr

@@ -437,5 +437,10 @@ module Spectator::DSL
     def no_args
       ::Spectator::Arguments.none
     end
+
+    # Indicates any arguments can be used (no constraint).
+    def any_args
+      ::Spectator::Arguments.any
+    end
   end
 end

src/spectator/mocks/arguments.cr

@@ -25,6 +25,11 @@ module Spectator
     # Instance of empty arguments.
     class_getter none : AbstractArguments = capture
 
+    # Returns unconstrained arguments.
+    def self.any : AbstractArguments?
+      nil.as(AbstractArguments?)
+    end
+
     # Returns the positional argument at the specified index.
     def [](index : Int)
       @args[index]

src/spectator/mocks/exception_stub.cr

@@ -12,7 +12,7 @@ module Spectator
     end
 
     # Returns a new stub with constrained arguments.
-    def with_constraint(constraint : AbstractArguments)
+    def with_constraint(constraint : AbstractArguments?)
       self.class.new(method, @exception, constraint, location)
     end
 

src/spectator/mocks/multi_value_stub.cr

@@ -16,7 +16,7 @@ module Spectator
     end
 
     # Returns a new stub with constrained arguments.
-    def with_constraint(constraint : AbstractArguments)
+    def with_constraint(constraint : AbstractArguments?)
       self.class.new(method, @values, constraint, location)
     end
 

src/spectator/mocks/null_stub.cr

@@ -9,7 +9,7 @@ module Spectator
     end
 
     # Returns a new stub with constrained arguments.
-    def with_constraint(constraint : AbstractArguments)
+    def with_constraint(constraint : AbstractArguments?)
       self.class.new(method, constraint, location)
     end
   end

src/spectator/mocks/proc_stub.cr

@@ -11,7 +11,7 @@ module Spectator
     end
 
     # Returns a new stub with constrained arguments.
-    def with_constraint(constraint : AbstractArguments)
+    def with_constraint(constraint : AbstractArguments?)
       self.class.new(method, @proc, constraint, location)
     end
 

src/spectator/mocks/stub_modifiers.cr

@@ -4,18 +4,18 @@ module Spectator
   # Mixin intended for `Stub` to return new, modified stubs.
   module StubModifiers
     # Returns a new stub of the same type with constrained arguments.
-    abstract def with_constraint(constraint : AbstractArguments)
+    abstract def with_constraint(constraint : AbstractArguments?)
+
+    # :ditto:
+    @[AlwaysInline]
+    def with(constraint : AbstractArguments?)
+      with_constraint(constraint)
+    end
 
     # :ditto:
     def with(*args, **kwargs)
       constraint = Arguments.new(args, kwargs).as(AbstractArguments)
       self.with_constraint(constraint)
     end
-
-    # :ditto:
-    @[AlwaysInline]
-    def with(constraint : AbstractArguments)
-      with_constraint(constraint)
-    end
   end
 end

src/spectator/mocks/value_stub.cr

@@ -12,7 +12,7 @@ module Spectator
     end
 
     # Returns a new stub with constrained arguments.
-    def with_constraint(constraint : AbstractArguments)
+    def with_constraint(constraint : AbstractArguments?)
       self.class.new(method, @value, constraint, location)
     end