Frl Test Coding Standard

Always apply the frl-coding-standard skill in addition to the standards below.

Choosing the right test type

When in doubt, prefer yaml-tests for anything reachable through SQL.

yaml-tests

Creating a new yamsql test file

1. Create yaml-tests/src/test/resources/<feature>-tests.yamsql.
2. Register it in yaml-tests/src/test/java/YamlIntegrationTests.java with a @YamlTest annotated method:

   @YamlTest(schemaTemplateFiles = {}, queryFiles = "my-feature-tests.yamsql")
   void myFeatureTests(YamlTest.Runner runner) throws Exception {
       runner.runYamsql();
   }
   

3. Decorate with @MaintainYamlTestConfig(YamlTestConfigFilters.CORRECT_EXPECTATIONS) to have the framework auto-populate expected query plans, metrics, and metadata on first run. Remove the annotation once the expected values are stable and reviewed.

yamsql file structure

See yaml-tests/src/test/resources/showcasing-tests.yamsql for a full reference. Key building blocks:

options:
  supported_version: 1.0.0     # minimum FRL version required

schema_template:               # declarative schema — reused across test blocks
  create table t (id bigint, name string, primary key(id))

setup:                         # DML run once before the test block
  - query: insert into t values (1, 'Alice'), (2, 'Bob')

test_block:
  preset: single_repetition_ordered
  tests:
    - query: select * from t where id = 1
      result:
        - [1, Alice]
    - query: explain select * from t where id = 1
      explain: "COVERING(...)"   # auto-filled by CORRECT_EXPECTATIONS on first run

Common result matchers: !ignore, !l (Long literal), !null, !not_null, !sc <substring> (string contains), !pos <value> (positional).

Debugging a yaml test

Add @DebugPlanner to the test method to launch PlannerRepl and inspect the plan interactively.

JUnit tests

• Use JUnit 6 exclusively. No junit.framework or org.junit.Assert (checkstyle-banned).
• Use AssertJ for assertions (org.assertj.core.api.Assertions).
• Test method naming: <methodUnderTest><Condition><ExpectedResult>.
• Extract shared setup into @BeforeEach or helper methods; DRY up after writing.

What not to do

• Do not use Thread.sleep() to wait for async operations — use asyncToSync() or CompletableFuture composition.
• Do not call join() or get() directly in test code if asyncToSync() is available on the context — it gives better error messages and timeout behavior.