Configure matcher to record_errors

Closes [#51].

Extract `JsonMatchers::Validator` to encapsulate error reporting
behavior.

`JSON::Validator` exposes a `#validate!` method that will raise on
validation failures, and a `#fully_validate!` method that won't raise,
but will return an array of error messages instead.

[#51]: #51

lib/json_matchers/matcher.rb

@@ -1,5 +1,5 @@
 require "json-schema"
-require "json_matchers/payload"
+require "json_matchers/validator"
 
 module JsonMatchers
   class Matcher
@@ -9,47 +9,37 @@ def initialize(schema_path, options = {})
     end
 
     def matches?(response)
-      # validate! will not raise and will always return true if you configure
-      # the validator to record errors, so we must instead inspect
-      # fully_validate's errors response
-      if options[:record_errors]
-        errors = JSON::Validator.fully_validate(
-          schema_path.to_s,
-          Payload.new(response).to_s,
-          options,
-        )
-
-        # errors is an array, but it will always only return a single item
-        if errors.any?
-          @validation_failure_message = errors.first
-          false
-        else
-          true
-        end
-      else
-        JSON::Validator.validate!(
-          schema_path.to_s,
-          Payload.new(response).to_s,
-          options,
-        )
-      end
-    rescue JSON::Schema::ValidationError => ex
-      @validation_failure_message = ex.message
+      validator = build_validator(response)
+
+      self.errors = validator.validate!
+
+      errors.empty?
+    rescue JSON::Schema::ValidationError => error
+      self.errors = [error.message]
       false
     rescue JSON::Schema::JsonParseError
       raise InvalidSchemaError
     end
 
     def validation_failure_message
-      @validation_failure_message.to_s
+      errors.first.to_s
     end
 
     private
 
     attr_reader :schema_path, :options
+    attr_accessor :errors
 
     def default_options
       JsonMatchers.configuration.options || {}
     end
+
+    def build_validator(response)
+      Validator.new(
+        options: options,
+        response: response,
+        schema_path: schema_path,
+      )
+    end
   end
 end

lib/json_matchers/validator.rb

@@ -0,0 +1,38 @@
+require "json-schema"
+require "json_matchers/payload"
+
+module JsonMatchers
+  class Validator
+    def initialize(options:, response:, schema_path:)
+      @options = options.dup
+      @payload = Payload.new(response).to_s
+      @schema_path = schema_path.to_s
+    end
+
+    def validate!
+      if recording_errors?
+        validate_recording_errors
+      else
+        validate
+      end
+    end
+
+    private
+
+    attr_reader :options, :payload, :schema_path
+
+    def recording_errors?
+      options.fetch(:record_errors, false)
+    end
+
+    def validate_recording_errors
+      JSON::Validator.fully_validate(schema_path, payload, options)
+    end
+
+    def validate
+      JSON::Validator.validate!(schema_path, payload, options)
+
+      []
+    end
+  end
+end