Testing Doobie Interpreter Using Testcontainers - postgresql

Question

I'm trying to test some SQL statements developed with doobie using Testcontainers libraries. In detail, I'm using the following dependencies:
"org.testcontainers" % "testcontainers" % "1.17.3" % Test,
"org.testcontainers" % "postgresql" % "1.17.3" % Test
My domain model is straightforward:
final case class Company(id: Int, name: String, description: String)
I create the table on PostgreSQL using an init script:
CREATE TABLE companies (
id serial NOT NULL,
name text NOT NULL,
description text
);
ALTER TABLE companies
ADD CONSTRAINT pk_companies PRIMARY KEY (id);
I'm trying to develop an integration test that verifies the insertion of a new Company. I'm using scalatest:
"org.scalatest" %% "scalatest" % scalaTestVersion % Test,
"org.typelevel" %% "cats-effect-testing-scalatest" % scalaTestCatsEffectVersion % Test
The code of the test is the following:
class CompaniesSpec extends AsyncFreeSpec with AsyncIOSpec with BeforeAndAfter with Matchers {
private val transactor: Resource[IO, Transactor[IO]] = for {
postgres <- makePostgres
ce <- ExecutionContexts.fixedThreadPool[IO](1)
xa <- HikariTransactor.newHikariTransactor[IO](
"org.postgresql.Driver",
postgres.getJdbcUrl,
postgres.getUsername,
postgres.getPassword,
ce
)
} yield xa
private def makePostgres =
Resource.make(IO {
val container: PostgreSQLContainer[Nothing] =
new PostgreSQLContainer().withInitScript("sql/companies.sql")
container.start()
container
})(c => IO(c.stop()))
"Companies algebra " - {
"should create a new Company" in {
(for {
companyId <- transactor.use { xa =>
sql"INSERT INTO companies (name, description) VALUES ('My Company', 'My Company Description')"
.update
.withUniqueGeneratedKeys[Int]("id")
.transact(xa)
}
maybeCompany <- transactor.use { xa =>
sql"SELECT * FROM companies WHERE id = $companyId"
.query[Company]
.option
.transact(xa)
}
} yield maybeCompany)
.asserting { company =>
company shouldBe defined
company.get.name shouldBe "My Company"
company.get.description shouldBe "My Company Description"
}
}
}
}
However, the test's assertions fail with the following error, which indicates that the code is not inserting anything into the database.
None was not defined
ScalaTestFailureLocation: com.rockthejvm.board.playground.algebras.CompaniesSpec at (CompaniesSpec.scala:68)
I really can't understand why the test is failing.
Can anyone help me?

Answer 1

makePostgres is a Resource which you compose with the HikariTransactor into the transaction Resource. That means that every time you call transaction.use{ ... } a new container is started and a new hikari connection pool is started. When the code in use finishes both are stopped.
Because you execute both queries in a different transactor.use{ ... } block they both run in a different container and on a different connection pool.
Instead you should make sure you use the same resources throughout your test.
transactor.use { xa =>
for {
companyId <-
sql"INSERT INTO companies (name, description) VALUES ('My Company', 'My Company Description')"
.update
.withUniqueGeneratedKeys[Int]("id")
.transact(xa)
maybeCompany <-
sql"SELECT * FROM companies WHERE id = $companyId"
.query[Company]
.option
.transact(xa)
} yield maybeCompany
}
.asserting { company =>
company shouldBe defined
company.get.name shouldBe "My Company"
company.get.description shouldBe "My Company Description"
}