add .default_strategy method to all adapters, and move knowledge into it from core.

Author: botandrose-machine

adapters/database_cleaner-active_record/lib/database_cleaner/active_record/base.rb

@@ -4,11 +4,14 @@
 
 module DatabaseCleaner
   module ActiveRecord
-
     def self.available_strategies
       %w[truncation transaction deletion]
     end
 
+    def self.default_strategy
+      :transaction
+    end
+
     def self.config_file_location=(path)
       @config_file_location = path
     end

adapters/database_cleaner-active_record/spec/database_cleaner/active_record/base_spec.rb

@@ -11,6 +11,10 @@ def self.connection
 RSpec.describe DatabaseCleaner::ActiveRecord do
   it { is_expected.to respond_to(:available_strategies) }
 
+  it "has a default_strategy of transaction" do
+    expect(described_class.default_strategy).to eq(:transaction)
+  end
+
   describe "config_file_location" do
     after do
       # prevent global state leakage

adapters/database_cleaner-couch_potato/lib/database_cleaner/couch_potato.rb

@@ -3,3 +3,9 @@
 require "database_cleaner/couch_potato/base"
 require "database_cleaner/couch_potato/truncation"
 
+module DatabaseCleaner::CouchPotato
+  def self.default_strategy
+    :truncation
+  end
+end
+

adapters/database_cleaner-couch_potato/spec/database_cleaner/couch_potato/base_spec.rb

@@ -0,0 +1,8 @@
+require 'database_cleaner/couch_potato'
+
+RSpec.describe DatabaseCleaner::CouchPotato do
+  it "has a default_strategy of truncation" do
+    expect(described_class.default_strategy).to eq(:truncation)
+  end
+end
+

adapters/database_cleaner-data_mapper/lib/database_cleaner/data_mapper/base.rb

@@ -5,6 +5,10 @@ def self.available_strategies
       %w[truncation transaction]
     end
 
+    def self.default_strategy
+      :transaction
+    end
+
     module Base
       include ::DatabaseCleaner::Generic::Base
 

adapters/database_cleaner-data_mapper/spec/database_cleaner/data_mapper/base_spec.rb

@@ -4,6 +4,10 @@
 module DatabaseCleaner
   RSpec.describe DataMapper do
     it { is_expected.to respond_to(:available_strategies) }
+
+    it "has a default_strategy of transaction" do
+      expect(described_class.default_strategy).to eq(:transaction)
+    end
   end
 
   module DataMapper

adapters/database_cleaner-mongo/lib/database_cleaner/mongo.rb

@@ -1,3 +1,10 @@
 require 'database_cleaner/mongo/version'
 require 'database_cleaner'
 require 'database_cleaner/mongo/truncation'
+
+module DatabaseCleaner::Mongo
+  def self.default_strategy
+    :truncation
+  end
+end
+

adapters/database_cleaner-mongo/spec/database_cleaner/mongo/base_spec.rb

@@ -0,0 +1,8 @@
+require 'database_cleaner/mongo'
+
+RSpec.describe DatabaseCleaner::Mongo do
+  it "has a default_strategy of truncation" do
+    expect(described_class.default_strategy).to eq(:truncation)
+  end
+end
+

adapters/database_cleaner-mongo_mapper/lib/database_cleaner/mongo_mapper/base.rb

@@ -5,6 +5,10 @@ def self.available_strategies
       %w[truncation]
     end
 
+    def self.default_strategy
+      :truncation
+    end
+
     module Base
       include ::DatabaseCleaner::Generic::Base
 

adapters/database_cleaner-mongo_mapper/spec/database_cleaner/mongo_mapper/base_spec.rb

@@ -4,6 +4,10 @@
 module DatabaseCleaner
   RSpec.describe MongoMapper do
     it { is_expected.to respond_to(:available_strategies) }
+
+    it "has a default_strategy of truncation" do
+      expect(described_class.default_strategy).to eq(:truncation)
+    end
   end
 
   module MongoMapper