Merge branch 'master' into laurocaetano-fix_send_file

* master: (536 commits)
  doc, API example on how to use `Model#exists?` with multiple IDs. [ci skip]
  Restore DATABASE_URL even if it's nil in connection_handler test
  [ci skip] - error_messages_for has been deprecated since 2.3.8 - lets reduce any confusion for users
  Ensure Active Record connection consistency
  Revert "ask the fixture set for the sql statements"
  Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
  Adding Hash#compact and Hash#compact! methods
  MySQL version 4.1 was EOL on December 31, 2009 We should at least recommend modern versions of MySQL to users.
  clear cache on body close so that cache remains during rendering
  add a more restricted codepath for templates fixes #13390
  refactor generator tests to use block form of Tempfile
  Fix typo [ci skip]
  Move finish_template as the last public method in the generator
  Minor typos fix [ci skip]
  make `change_column_null` reversible. Closes #13576.
  create/drop test and development databases only if RAILS_ENV is nil
  Revert "Speedup String#to"
  typo fix in test name. [ci skip].
  `core_ext/string/access.rb` test what we are documenting.
  Fix typo in image_tag documentation
  ...

Conflicts:
	actionpack/CHANGELOG.md

1 files changed, 127 insertions, 0 deletions

diff --git a/activerecord/test/cases/connection_adapters/connection_handler_test.rb b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
index 3e33b30144..318cc5a32c 100644
--- a/activerecord/test/cases/connection_adapters/connection_handler_test.rb
+++ b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
@@ -2,6 +2,133 @@ require "cases/helper"
 
 module ActiveRecord
   module ConnectionAdapters
+
+    class MergeAndResolveDefaultUrlConfigTest < ActiveRecord::TestCase
+
+      def klass
+        ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig
+      end
+
+      def setup
+        @previous_database_url = ENV.delete("DATABASE_URL")
+      end
+
+      def teardown
+        ENV["DATABASE_URL"] = @previous_database_url
+      end
+
+      def test_string_connection
+        config   = { "production" => "postgres://localhost/foo" }
+        actual   = klass.new(config).resolve
+        expected = { "production" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_url_sub_key
+        config   = { "production" => { "url" => "postgres://localhost/foo" } }
+        actual   = klass.new(config).resolve
+        expected = { "production" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_hash
+        config = { "production" => { "adapter" => "postgres", "database" => "foo" } }
+        actual = klass.new(config).resolve
+        assert_equal config, actual
+      end
+
+      def test_blank
+        config = {}
+        actual = klass.new(config).resolve
+        assert_equal config, actual
+      end
+
+      def test_blank_with_database_url
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+
+        config   = {}
+        actual   = klass.new(config).resolve
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "localhost" }
+        assert_equal expected, actual["production"]
+        assert_equal expected, actual["development"]
+        assert_equal expected, actual["test"]
+        assert_equal nil,      actual[:production]
+        assert_equal nil,      actual[:development]
+        assert_equal nil,      actual[:test]
+      end
+
+      def test_sting_with_database_url
+        ENV['DATABASE_URL'] = "NOT-POSTGRES://localhost/NOT_FOO"
+
+        config   = { "production" => "postgres://localhost/foo" }
+        actual   = klass.new(config).resolve
+
+        expected = { "production" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_url_sub_key_with_database_url
+        ENV['DATABASE_URL'] = "NOT-POSTGRES://localhost/NOT_FOO"
+
+        config   = { "production" => { "url" => "postgres://localhost/foo" } }
+        actual   = klass.new(config).resolve
+        expected = { "production" =>
+                    { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_merge_no_conflicts_with_database_url
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+
+        config   = {"production" => { "pool" => "5" } }
+        actual   = klass.new(config).resolve
+        expected = { "production" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost",
+                       "pool"     => "5"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+
+      def test_merge_conflicts_with_database_url
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+
+        config   = {"production" => { "adapter" => "NOT-POSTGRES", "database" => "NOT-FOO", "pool" => "5" } }
+        actual   = klass.new(config).resolve
+        expected = { "production" =>
+                     { "adapter"  => "postgresql",
+                       "database" => "foo",
+                       "host"     => "localhost",
+                       "pool"     => "5"
+                      }
+                    }
+        assert_equal expected, actual
+      end
+    end
+
     class ConnectionHandlerTest < ActiveRecord::TestCase
       def setup
         @klass    = Class.new(Base)   { def self.name; 'klass';    end }