Fix handling disabled schema dumping for test environment

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -365,6 +365,7 @@ def structure_load(configuration, *arguments)
 
       def load_schema(db_config, format = ActiveRecord.schema_format, file = nil) # :nodoc:
         file ||= schema_dump_path(db_config, format)
+        return unless file
 
         verbose_was, Migration.verbose = Migration.verbose, verbose? && ENV["VERBOSE"]
         check_schema_file(file)
@@ -390,7 +391,7 @@ def schema_up_to_date?(configuration, format = ActiveRecord.schema_format, file
 
         file ||= schema_dump_path(db_config)
 
-        return true unless File.exist?(file)
+        return true unless file && File.exist?(file)
 
         ActiveRecord::Base.establish_connection(db_config)
 
@@ -403,7 +404,7 @@ def schema_up_to_date?(configuration, format = ActiveRecord.schema_format, file
       def reconstruct_from_schema(db_config, format = ActiveRecord.schema_format, file = nil) # :nodoc:
         file ||= schema_dump_path(db_config, format)
 
-        check_schema_file(file)
+        check_schema_file(file) if file
 
         ActiveRecord::Base.establish_connection(db_config)
 
@@ -421,6 +422,8 @@ def reconstruct_from_schema(db_config, format = ActiveRecord.schema_format, file
       def dump_schema(db_config, format = ActiveRecord.schema_format) # :nodoc:
         require "active_record/schema_dumper"
         filename = schema_dump_path(db_config, format)
+        return unless filename
+
         connection = ActiveRecord::Base.connection
 
         FileUtils.mkdir_p(db_dir)

railties/test/application/rake/multi_dbs_test.rb

@@ -1024,6 +1024,27 @@ class TwoMigration < ActiveRecord::Migration::Current
         end
       end
 
+      test "db:test:prepare don't raise errors when schema_dump is false" do
+        app_file "config/database.yml", <<~EOS
+          development: &development
+            primary:
+              adapter: sqlite3
+              database: dev_db
+              schema_dump: false
+            secondary:
+              adapter: sqlite3
+              database: secondary_dev_db
+              schema_dump: false
+          test:
+            <<: *development
+        EOS
+
+        Dir.chdir(app_path) do
+          output = rails("db:test:prepare", "--trace")
+          assert_match(/Execute db:test:prepare/, output)
+        end
+      end
+
       test "db:create and db:drop don't raise errors when loading YAML containing multiple ERB statements on the same line" do
         app_file "config/database.yml", <<-YAML
           development: