Fix `bin/rails db:setup` and `bin/rails db:test:prepare` create wrong ar_internal_metadata's data for a test database.

  Before:
  ```
  $ RAILS_ENV=test rails dbconsole
  > SELECT * FROM ar_internal_metadata;
  key|value|created_at|updated_at
  environment|development|2017-09-11 23:14:10.815679|2017-09-11 23:14:10.815679
  ```

  After:
  ```
  $ RAILS_ENV=test rails dbconsole
  > SELECT * FROM ar_internal_metadata;
  key|value|created_at|updated_at
  environment|test|2017-09-11 23:14:10.815679|2017-09-11 23:14:10.815679
  ```

  Fixes #26731.

3 files changed, 33 insertions, 9 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 9cca2c4c5a..06d52ee1fa 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,26 @@
+*   Fix `bin/rails db:setup` and `bin/rails db:test:prepare` create  wrong
+    ar_internal_metadata's data for a test database.
+
+    Before:
+    ```
+    $ RAILS_ENV=test rails dbconsole
+    > SELECT * FROM ar_internal_metadata;
+    key|value|created_at|updated_at
+    environment|development|2017-09-11 23:14:10.815679|2017-09-11 23:14:10.815679
+    ```
+
+    After:
+    ```
+    $ RAILS_ENV=test rails dbconsole
+    > SELECT * FROM ar_internal_metadata;
+    key|value|created_at|updated_at
+    environment|test|2017-09-11 23:14:10.815679|2017-09-11 23:14:10.815679
+    ```
+
+    Fixes #26731.
+
+    *bogdanvlviv*
+
 *   Fix longer sequence name detection for serial columns.
 
     Fixes #28332.
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index 691b3612d8..eb32c29b7e 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -313,7 +313,7 @@ db_namespace = namespace :db do
       begin
         should_reconnect = ActiveRecord::Base.connection_pool.active_connection?
         ActiveRecord::Schema.verbose = false
-        ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :ruby, ENV["SCHEMA"]
+        ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :ruby, ENV["SCHEMA"], "test"
       ensure
         if should_reconnect
           ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations[ActiveRecord::Tasks::DatabaseTasks.env])
@@ -323,7 +323,7 @@ db_namespace = namespace :db do
 
     # desc "Recreate the test database from an existent structure.sql file"
     task load_structure: %w(db:test:purge) do
-      ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :sql, ENV["SCHEMA"]
+      ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :sql, ENV["SCHEMA"], "test"
     end
 
     # desc "Empty the test database"
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index 0f3f84ca08..0b85965bab 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -225,7 +225,7 @@ module ActiveRecord
         class_for_adapter(configuration["adapter"]).new(*arguments).structure_load(filename, structure_load_flags)
       end
 
-      def load_schema(configuration, format = ActiveRecord::Base.schema_format, file = nil) # :nodoc:
+      def load_schema(configuration, format = ActiveRecord::Base.schema_format, file = nil, environment = env) # :nodoc:
         file ||= schema_file(format)
 
         case format
@@ -240,7 +240,7 @@ module ActiveRecord
           raise ArgumentError, "unknown format #{format.inspect}"
         end
         ActiveRecord::InternalMetadata.create_table
-        ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment
+        ActiveRecord::InternalMetadata[:environment] = environment
       end
 
       def schema_file(format = ActiveRecord::Base.schema_format)
@@ -253,8 +253,8 @@ module ActiveRecord
       end
 
       def load_schema_current(format = ActiveRecord::Base.schema_format, file = nil, environment = env)
-        each_current_configuration(environment) { |configuration|
-          load_schema configuration, format, file
+        each_current_configuration(environment) { |configuration, configuration_environment|
+          load_schema configuration, format, file, configuration_environment
         }
         ActiveRecord::Base.establish_connection(environment.to_sym)
       end
@@ -301,9 +301,10 @@ module ActiveRecord
           environments = [environment]
           environments << "test" if environment == "development"
 
-          configurations = ActiveRecord::Base.configurations.values_at(*environments)
-          configurations.compact.each do |configuration|
-            yield configuration unless configuration["database"].blank?
+          ActiveRecord::Base.configurations.slice(*environments).each do |configuration_environment, configuration|
+            next unless configuration["database"]
+
+            yield configuration, configuration_environment
           end
         end