Using pattern matchers in tests

[filiphornak]

Context

In PR #791 (comment) we discussed with @jozefbakus an option to use pattern matching in scala test. This will reduce the boilerplate for testing that Option, Try, Either, or any other sum type has a good result.

Here is an actual example taken from ChekpointServiceTest

result.size shouldBe 2
result.head._1 shouldBe "my.topic"
result.head._2 should contain theSameElementsAs Map(2 -> 2021L, 1 -> 1021L, 3 -> 3021L, 0 -> 21L)
result.toSeq(1)._1 shouldBe "my.other.topic"
result.toSeq(1)._2 should contain theSameElementsAs Map(0 -> 0L)

which could be reduced to

result shouldBe Seq(
  ("my.topic", Map(0 -> 21L, 1 -> 1021L, 2 -> 2021L, 3 -> 3021L)),
  ("my.other.topic", Map(0 -> 0L))
)

or if we don't care about exact values, we can use `should matchPatter { case => }

val result = underTest.getLatestCommittedOffset(params)(ugi)

result.get.isDefined shouldBe true
result.get shouldBe Some(offsets)

which will become

result should matchPattern { case Success(Some(_)) => }

Objective

• Rewrite tests to use appropriate matchers https://www.scalatest.org/user_guide/using_matchers
• Ensure that all the cases as covered as they were before refactoring

[kevinwallimann]

val result = underTest.getLatestCommittedOffset(params)(ugi)

result.get.isDefined shouldBe true
result.get shouldBe Some(offsets)

should be replaced with

val result = underTest.getLatestCommittedOffset(params)(ugi)

result shouldBe Success(Some(offsets))

[kevinwallimann]

In this example

result shouldBe Seq(
  ("my.topic", Map(0 -> 21L, 1 -> 1021L, 2 -> 2021L, 3 -> 3021L)),
  ("my.other.topic", Map(0 -> 0L))
)

what we would really like to do is something like this

result shouldBe Seq(
  ("my.topic", theSameElementsAs(Map(0 -> 21L, 1 -> 1021L, 2 -> 2021L, 3 -> 3021L))),
  ("my.other.topic", Map(0 -> 0L))
)

especially if it wasn't a Map, but a Seq.

[kevinwallimann]

https://www.scalatest.org/scaladoc/3.2.4/org/scalatest/Inspectors.html