Make 'migrate' clear the schema cache afterward

Without clearing the caches afterward, removals done in migrations would
not be reflected in a separate task in the same process. That is, given
a table with a migration to remove a column, the schema cache would
still reflect that a table has that in something such as the
'db:seed' task:

`rake db:migrate db:seed`
(A common thing to do in a script for a project ala `bin/setup`)

vs

`rake db:migrate && rake db:seed`
(Two processes)

The first would not reflect that the column was removed.
The second would (cache reset).

1 files changed, 13 insertions, 2 deletions

diff --git a/activerecord/test/cases/tasks/database_tasks_test.rb b/activerecord/test/cases/tasks/database_tasks_test.rb
index 429aeca1d9..0aac5bad31 100644
--- a/activerecord/test/cases/tasks/database_tasks_test.rb
+++ b/activerecord/test/cases/tasks/database_tasks_test.rb
@@ -309,19 +309,30 @@ module ActiveRecord
   end
 
   class DatabaseTasksMigrateTest < ActiveRecord::TestCase
+    def setup
+      ActiveRecord::Tasks::DatabaseTasks.migrations_paths = 'custom/path'
+    end
+
+    def teardown
+      ActiveRecord::Tasks::DatabaseTasks.migrations_paths = nil
+    end
+
     def test_migrate_receives_correct_env_vars
       verbose, version = ENV['VERBOSE'], ENV['VERSION']
 
-      ActiveRecord::Tasks::DatabaseTasks.migrations_paths = 'custom/path'
       ENV['VERBOSE'] = 'false'
       ENV['VERSION'] = '4'
 
       ActiveRecord::Migrator.expects(:migrate).with('custom/path', 4)
       ActiveRecord::Tasks::DatabaseTasks.migrate
     ensure
-      ActiveRecord::Tasks::DatabaseTasks.migrations_paths = nil
       ENV['VERBOSE'], ENV['VERSION'] = verbose, version
     end
+
+    def test_migrate_clears_schema_cache_afterward
+      ActiveRecord::Base.expects(:clear_cache!)
+      ActiveRecord::Tasks::DatabaseTasks.migrate
+    end
   end
 
   class DatabaseTasksPurgeTest < ActiveRecord::TestCase