Question

I am trying to write some code to test a database model. Both the test framework and the database framework use the “===” operator, and the test framework’s is being given preference. How can I explicitly use one method or the other?

Example:

import org.scalatest.FunSuite

class TestDBModels extends FunSuite{
  test("Test DoublePropertyEntry with a few new values") {
    Schemas.doubleProperties.deleteWhere(p => (p.id === p.id)))
  }
}

Error:

type mismatch;
found   : Option[String]
required: org.squeryl.dsl.ast.LogicalBoolean
Schemas.doubleProperties.deleteWhere(p => (p.===(p.id, p.id)))

Answer 1

You have a number of options. The first and easiest is to use an explicit method call instead of the implicit conversion. For example, to explicitly use the scalatest ===:

Schemas.doubleProperties.deleteWhere(p => (convertToEqualizer(p.id) === p.id)))

If this is too long, you could shorten the name:

def toEq(left: Any) = convertToEqualizer(left: Any)
Schemas.doubleProperties.deleteWhere(p => (toEq(p.id) === p.id)))

convertToEqualizer is the implicit conversion method for scalatest. One other option is to override convertToEqualizer as a non-implicit method:

override def convertToEqualizer(left: Any) = new Equalizer(left)

This stops this particular implicit conversion happening. See the scalatest documentation for Assertions object and the same question on the scalatest-users mailing list.