Load test schema even if there are no migrations

Fixes #17170

activerecord/lib/active_record/migration.rb

@@ -394,7 +394,7 @@ module ActiveRecord
       end
 
       def load_schema_if_pending!
-        if ActiveRecord::Migrator.needs_migration?
+        if ActiveRecord::Migrator.needs_migration? || !ActiveRecord::Migrator.any_migrations?
           ActiveRecord::Tasks::DatabaseTasks.load_schema_current
           check_pending!
         end
@@ -848,6 +848,10 @@ module ActiveRecord
         (migrations(migrations_paths).collect(&:version) - get_all_versions(connection)).size > 0
       end
 
+      def any_migrations?
+        migrations(migrations_paths).any?
+      end
+
       def last_version
         last_migration.version
       end

activerecord/test/cases/migration_test.rb

@@ -100,6 +100,19 @@ class MigrationTest < ActiveRecord::TestCase
     ActiveRecord::Migrator.migrations_paths = old_path
   end
 
+  def test_any_migrations
+    old_path = ActiveRecord::Migrator.migrations_paths
+    ActiveRecord::Migrator.migrations_paths = MIGRATIONS_ROOT + "/valid"
+
+    assert ActiveRecord::Migrator.any_migrations?
+
+    ActiveRecord::Migrator.migrations_paths = MIGRATIONS_ROOT + "/empty"
+
+    assert_not ActiveRecord::Migrator.any_migrations?
+  ensure
+    ActiveRecord::Migrator.migrations_paths = old_path
+  end
+
   def test_migration_version
     ActiveRecord::Migrator.run(:up, MIGRATIONS_ROOT + "/version_check", 20131219224947)
   end