Slick TestKit
When you write your own database profile for Slick, you need a way to run all the standard unit tests on it (in addition to any custom tests you may want to add) to ensure that it works correctly and does not claim to support any capabilities which are not actually implemented. For this purpose the Slick unit tests have been factored out into a separate Slick TestKit project.
To get started, you can download the TestKit Example project which contains a copy of Slick’s standard PostgreSQL profile and all the infrastructure required to build and test it.
Scaffolding
Its build.sbt
file is straight-forward. It adds the dependencies for Slick, TestKit, junit-interface, Logback and the PostgreSQL JDBC driver, and it sets some options for the test runs:
sourceimport _root_.io.github.nafg.mergify.dsl._
mergifyExtraConditions := Seq(
(Attr.Author :== "scala-steward") ||
(Attr.Author :== "slick-scala-steward[bot]") ||
(Attr.Author :== "renovate[bot]")
)
libraryDependencies ++= List(
"com.github.sbt" % "junit-interface" % "0.13.3" % Test,
"ch.qos.logback" % "logback-classic" % "1.5.5" % Test,
"org.postgresql" % "postgresql" % "42.7.3" % Test,
)
scalacOptions += "-deprecation"
Test / parallelExecution := false
logBuffered := false
run / fork := true
testOptions += Tests.Argument(TestFrameworks.JUnit, "-q", "-v", "-s", "-a")
libraryDependencies += "com.typesafe.slick" %% "slick-testkit" % "3.4.1"
ThisBuild / githubWorkflowBuildPreamble +=
WorkflowStep.Run(List("docker-compose up -d"), name = Some("Start database"))
There is a copy of Slick’s logback configuration in src/test/resources/logback-test.xml
but you can swap out the logging framework if you prefer a different one.
Profile
The actual profile implementation can be found under src/main/scala
:
sourcepackage com.example
trait MyPostgresProfile extends JdbcProfile {
// ...
}
object MyPostgresProfile extends MyPostgresProfile
Test Harness
In order to run the TestKit tests, you need to add a class that extends ProfileTest
, plus an implementation of TestDB
which tells TestKit how to connect to a test database, get a list of tables, clean up between tests, etc.
In the case of the PostgreSQL test harness (in src/test/scala/MyPostgresTest.scala
) most of the default implementations can be used out of the box. Only localTables
and getLocalSequences
require custom implementations. We also modify the profile’s capabilities
to indicate that our profile does not support the JDBC getFunctions
call:
source@RunWith(classOf[Testkit])
class MyPostgresTest extends ProfileTest(MyPostgresTest.tdb)
object MyPostgresTest {
def tdb = new ExternalJdbcTestDB("mypostgres") {
val profile = MyPostgresProfile
override def localTables(implicit ec: ExecutionContext): DBIO[Vector[String]] =
ResultSetAction[(String,String,String, String)](_.conn.getMetaData().getTables("", "public", null, null)).map { ts =>
ts.filter(_._4.toUpperCase == "TABLE").map(_._3).sorted
}
override def localSequences(implicit ec: ExecutionContext): DBIO[Vector[String]] =
ResultSetAction[(String,String,String, String)](_.conn.getMetaData().getTables("", "public", null, null)).map { ts =>
ts.filter(_._4.toUpperCase == "SEQUENCE").map(_._3).sorted
}
override def capabilities = super.capabilities - TestDB.capabilities.jdbcMetaGetFunctions
}
}
The name of a configuration prefix, in this case mypostgres
, is passed to ExternalJdbcTestDB
:
sourcedef tdb = new ExternalJdbcTestDB("mypostgres") {
Database Configuration
Since the PostgreSQL test harness is based on ExternalJdbcTestDB
, it needs to be configured in test-dbs/testkit.conf
:
source# Enable the tests for mypostgres:
mypostgres.enabled = true
# Set the user name (default: "postgres")
mypostgres.user = "postgres"
# Set the password (default: no password)
mypostgres.password = postgres
mypostgres.create = CREATE DATABASE ${testDB} "TEMPLATE = template0"
mypostgres.baseURL = "jdbc:postgresql://localhost:54325/"
There are several other configuration options that need to be set for an ExternalJdbcTestDB
. These are defined with suitable defaults in testkit-reference.conf
so that testkit.conf
can be kept very simple in most cases:
sourcemypostgres {
baseURL = "jdbc:postgresql:"
user = postgres
adminDB = postgres
create = [
CREATE TABLESPACE slick_test LOCATION '${testkit.absTestDir}'
CREATE DATABASE ${testDB} "TEMPLATE = template0 TABLESPACE slick_test"
]
postCreate = "create extension lo"
drop = [
DROP DATABASE IF EXISTS ${testDB}
DROP TABLESPACE IF EXISTS slick_test
]
driver = org.postgresql.Driver
}
Testing
Running sbt test
discovers MyPostgresTest
and runs it with TestKit’s JUnit runner. This in turn causes the database to be set up through the test harness and all tests which are applicable for the profile (as determined by the capabilities
setting in the test harness) to be run.