Config stores the RNG instead of a seed

src/spectator.cr

@@ -78,7 +78,6 @@ module Spectator
 
   @@config_builder = ConfigBuilder.new
   @@config : Config?
-  @@random : Random?
 
   # Provides a means to configure how Spectator will run and report tests.
   # A `ConfigBuilder` is yielded to allow changing the configuration.
@@ -93,7 +92,7 @@ module Spectator
   # This provides reproducable results even though random values are used.
   # The seed for this random generator is controlled by `ConfigBuilder.seed=`.
   def random
-    @@random ||= Random.new(config.seed)
+    config.random
   end
 
   # Builds the tests and runs the framework.

src/spectator/config.cr

@@ -13,8 +13,8 @@ module Spectator
     # Examples won't run, but the output will show that they did.
     getter? dry_run : Bool
 
-    # Seed for the random number generator.
-    getter seed : Int32
+    # Random number generator to use for everything.
+    getter random : Random
 
     # Creates a new configuration.
     def initialize(builder)
@@ -22,7 +22,7 @@ module Spectator
       @fail_fast = builder.fail_fast?
       @fail_blank = builder.fail_blank?
       @dry_run = builder.dry_run?
-      @seed = builder.seed
+      @random = builder.random
     end
 
     # Yields each formatter that should be reported to.

src/spectator/config_builder.cr

@@ -8,8 +8,8 @@ module Spectator
       new.build
     end
 
-    # Seed for the random number generator.
-    property seed = 0
+    # Random number generator to use.
+    getter random = Random::DEFAULT
 
     @primary_formatter : Formatting::Formatter?
     @additional_formatters = [] of Formatting::Formatter
@@ -87,6 +87,10 @@ module Spectator
       @dry_run
     end
 
+    # Sets the seed for the random number generator.
+    def seed=(seed)
+      @random = Random.new(seed)
+    end
     # Creates a configuration.
     def build : Config
       Config.new(self)