Use shorter string when stub is treated as a message

spec/matchers/receive_matcher_spec.cr

@@ -296,7 +296,7 @@ Spectator.describe Spectator::Matchers::ReceiveMatcher do
       end
 
       it "has the expected call listed" do
-        is_expected.to contain({:expected, "Not #{stub}"})
+        is_expected.to contain({:expected, "Not #{stub.message}"})
       end
 
       it "has the list of called methods" do

src/spectator/matchers/receive_matcher.cr

@@ -81,7 +81,7 @@ module Spectator::Matchers
 
     # Short text about the matcher's purpose.
     def description : String
-      "received #{@stub} #{humanize_count}"
+      "received #{@stub.message} #{humanize_count}"
     end
 
     # Actually performs the test against the expression (value or block).
@@ -89,10 +89,10 @@ module Spectator::Matchers
       stubbed = actual.value
       calls = relevant_calls(stubbed)
       if @count.includes?(calls.size)
-        SuccessfulMatchData.new("#{actual.label} received #{@stub} #{humanize_count}")
+        SuccessfulMatchData.new("#{actual.label} received #{@stub.message} #{humanize_count}")
       else
-        FailedMatchData.new("#{actual.label} received #{@stub} #{humanize_count}",
+        FailedMatchData.new("#{actual.label} received #{@stub.message} #{humanize_count}",
-          "#{actual.label} did not receive #{@stub}", values(actual).to_a)
+          "#{actual.label} did not receive #{@stub.message}", values(actual).to_a)
       end
     end
 
@@ -106,9 +106,9 @@ module Spectator::Matchers
       stubbed = actual.value
       calls = relevant_calls(stubbed)
       if @count.includes?(calls.size)
-        FailedMatchData.new("#{actual.label} did not receive #{@stub}", "#{actual.label} received #{@stub}", negated_values(actual).to_a)
+        FailedMatchData.new("#{actual.label} did not receive #{@stub.message}", "#{actual.label} received #{@stub.message}", negated_values(actual).to_a)
       else
-        SuccessfulMatchData.new("#{actual.label} did not receive #{@stub} #{humanize_count}")
+        SuccessfulMatchData.new("#{actual.label} did not receive #{@stub.message} #{humanize_count}")
       end
     end
 
@@ -120,7 +120,7 @@ module Spectator::Matchers
     # Additional information about the match failure.
     private def values(actual : Expression(T)) forall T
       {
-        expected: @stub.to_s,
+        expected: @stub.message,
         actual:   method_call_list(actual.value),
       }
     end
@@ -128,7 +128,7 @@ module Spectator::Matchers
     # Additional information about the match failure when negated.
     private def negated_values(actual : Expression(T)) forall T
       {
-        expected: "Not #{@stub}",
+        expected: "Not #{@stub.message}",
         actual:   method_call_list(actual.value),
       }
     end

src/spectator/mocks/stub.cr

@@ -22,6 +22,23 @@ module Spectator
     def initialize(@method : Symbol, @constraint : AbstractArguments? = nil, @location : Location? = nil)
     end
 
+    # String representation of the stub, formatted as a method call.
+    def message(io : IO) : Nil
+      io << "#" << method << (constraint || "(any args)")
+    end
+
+    # String representation of the stub, formatted as a method call.
+    def message
+      String.build do |str|
+        message(str)
+      end
+    end
+
+    # String representation of the stub, formatted as a method definition.
+    def to_s(io : IO) : Nil
+      message(io)
+    end
+
     # Checks if a method call should receive the response from this stub.
     def ===(call : MethodCall)
       return false if method != call.method
@@ -29,10 +46,5 @@ module Spectator
 
       constraint === call.arguments
     end
-
-    # String representation of the stub, formatted as a method call.
-    def to_s(io : IO) : Nil
-      io << "#" << method << (constraint || "(any args)")
-    end
   end
 end