Testing

tursodatabase/turso/.claude/skills/testing

by tursodatabaseff97ec42cdefNo license24K starsListed Oct 9, 2026Updated Oct 8, 2026Repository updated today

How to write tests, when to use each type of test, and how to run them. Contains information about conversion of `.test` to `.sqltest`, and how to write `.sqltest` and rust tests

Instructions onlySoftware Development
AI-generated overview

Guide for writing and running SQL and Rust tests in a database project, including .sqltest, TCL and fuzz tests.

What it does
This skill documents a project's testing conventions: which test types exist (.sqltest, legacy TCL .test, Rust integration, fuzz), where each lives, and when to use each. It gives commands for running suites and single tests, templates for writing .sqltest, TCL and Rust tests, assertion-library examples, and rules such as requiring a test for every functional change. It also covers converting TCL tests to .sqltest and adjusting expected results for regenerated databases.
When to use it
Use it when adding, converting or running tests in this SQLite-compatible database codebase. It fits tasks such as writing a new .sqltest case, migrating a legacy TCL test, or choosing the right test type for a change.
Requirements
Requires the project's build and test tooling: make targets, a Rust toolchain with cargo, and the sqltest runner; no credentials or network access are described. It ships no scripts, only instructions.

Testing Guide

Test Types & When to Use

TypeLocationUse Case
.sqltestsqlite/conformance/sqlite-sqltests/SQL compatibility. Preferred for new tests
TCL .testtesting/Legacy SQL compat (being phased out)
Rust integrationtests/integration/Regression tests, complex scenarios
Fuzztests/fuzz/Complex features, edge case discovery

Note: TCL tests are being phased out in favor of the .sqltest suites in sqlite/conformance/. The .sqltest format allows the same test cases to run against multiple backends (CLI, Rust bindings, etc.).

Running Tests

bash
# Main test suite (TCL compat, sqlite3 compat, Python wrappers)make test
# Single TCL testmake test-single TEST=select.test
# SQL test runnermake -C sqlite/conformance run-cli
# ORcargo run -p sqltest -- run <test-file or directory>
# Rust unit/integration tests (full workspace)cargo test

Writing Tests

.sqltest (Preferred)

@database :default:
test example-addition {    SELECT 1 + 1;}expect {    2}
test example-multiple-rows {    SELECT id, name FROM users WHERE id < 3;}expect {    1|alice    2|bob}

Location: sqlite/conformance/sqlite-sqltests/*.sqltest

You must start converting TCL tests with the convert command from the test runner (e.g cargo run -- convert <TCL_test_path> -o <out_dir>). It is not always accurate, but it will convert most of the tests. If some conversion emits a warning you will have to write by hand whatever is missing from it (e.g unroll a for each loop by hand). Then you need to verify the tests work by running them with make -C sqlite/conformance run-rust, and adjust their output if something was wrong with the conversion. Also, we use harcoded databases in TCL, but with .sqltest we generate the database with a different seed, so you will probably need to change the expected test result to match the new database query output. Avoid changing the SQL statements from the test, just change the expected result

TCL

tcl
do_execsql_test_on_specific_db {:memory:} test-name {  SELECT 1 + 1;} {2}

Location: testing/*.test

Rust Integration

rust
// tests/integration/test_foo.rs#[test]fn test_something() {    let conn = Connection::open_in_memory().unwrap();    // ...}

Assertions

Prefer the asserting crate for anything more than trivial assertions. The assertions it offers are extensive and make tests more readable. Some simple examples:

rust
use asserting::prelude::*;
assert_that!(conn.execute("SELECT * FROM t1;")).is_err();assert_that_code!(|| parse(bad_input)).panics_with_message("unexpected token");
assert_that!(&rows)    .has_length(3)    .any_satisfies(|r| r    .name == "bob")    .first_element_ref()    .is_equal_to(&Row { id: 1, name: "alice".into() });
assert_that!(&header)    .named("page 2 header")    .satisfies_with_message("be a leaf table page", |h| h[0] == 0x0d);
// soft assertions: mark the test as failed but don't stopverify_that!(&plan)    .starts_with("SEARCH")    .contains("USING INDEX")    .soft_panic();

crate::assertions adds row! for result rows, plus column and query-plan assertions:

rust
use crate::assertions::{AssertColumn, AssertQueryPlan, Cell, NULL};
assert_that!(limbo_exec_rows(&conn, "SELECT id, name FROM t ORDER BY id"))    .is_equal_to(vec![row![1, "alice"], row![2, NULL]]);
assert_that!(limbo_exec_rows(&conn, "SELECT id FROM t WHERE id = 1"))    .single_element()    .is_equal_to(row![1]);
assert_that!(limbo_exec_rows(&conn, "SELECT id, name FROM t"))    .column(1)    .contains(Cell::from("alice"));
assert_that!(limbo_exec_rows(&conn, "EXPLAIN QUERY PLAN SELECT id FROM t WHERE name = 'a'"))    .uses_index("idx_name")    .searches_table("t")    .has_table_access_order(["t"]);

Key Rules

  • Every functional change needs a test
  • Test must fail without change, pass with it
  • Prefer in-memory DBs: :memory: (sqltest) or {:memory:} (TCL)
  • Don't invent new test formats. Follow existing patterns
  • Write tests first when possible

Test Database Schema

testing/system/testing.db has users and products tables. See docs/testing.md for schema.

Logging During Tests

bash
RUST_LOG=none,turso_core=trace make test

Output: testing/system/test.log. Warning: very verbose.

Source and attribution

Source:tursodatabase/tursoin.claude/skills/testingat commitff97ec4

License: No license

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