Store location information in stub

Allows tracking where a stub was originally defined.

src/spectator/dsl/mocks.cr

@@ -167,8 +167,8 @@ module Spectator::DSL
     # allow(dbl).to receive(:foo).and_return(42)
     # expect(dbl.foo).to eq(42)
     # ```
-    macro receive(method)
-      ::Spectator::NullStub.new({{method.id.symbolize}})
+    macro receive(method, *, _file = __FILE__, _line = __LINE__)
+      ::Spectator::NullStub.new({{method.id.symbolize}}, location: ::Spectator::Location.new({{_file}}, {{_line}}))
     end
   end
 end

src/spectator/mocks/stub.cr

@@ -12,8 +12,11 @@ module Spectator
     # Is nil when there's no constraint - only the method name must match.
     getter constraint : AbstractArguments?
 
+    # Location the stub was defined.
+    getter location : Location?
+
     # Creates the base of the stub.
-    def initialize(@method : Symbol, @constraint : AbstractArguments? = nil)
+    def initialize(@method : Symbol, @constraint : AbstractArguments? = nil, @location : Location? = nil)
     end
 
     # Checks if a method call should receive the response from this stub.

src/spectator/mocks/value_stub.cr

@@ -1,3 +1,4 @@
+require "../location"
 require "./arguments"
 require "./typed_stub"
 
@@ -10,8 +11,8 @@ module Spectator
     end
 
     # Creates the stub.
-    def initialize(method : Symbol, @value : T, constraint : AbstractArguments? = nil)
-      super(method, constraint)
+    def initialize(method : Symbol, @value : T, constraint : AbstractArguments? = nil, location : Location? = nil)
+      super(method, constraint, location)
     end
   end
 end