ScalaTest makes three assertions available by default in any style trait. You can use:
assertfor general assertions;
assertResultto differentiate expected from actual values;
interceptto ensure a bit of code throws an expected exception.
In any Scala program, you can write assertions by invoking
assert and passing in a
val left = 2 val right = 1 assert(left == right)
If the passed expression is
assert will return normally. If
assert will complete abruptly with an
AssertionError. This behavior is provided by
assert method defined in object
Predef, whose members are implicitly imported into every Scala source file.
ScalaTest provides a domain specific language (DSL) for expressing assertions in tests
using the word
should. ScalaTest matchers provides five different ways to check equality, each designed to address a different need. They are:
result should equal(3) // can customize equality result should ===(3) // can customize equality and enforce type constraints result should be(3) // cannot customize equality, so fastest to compile result shouldEqual 3 // can customize equality, no parentheses required result shouldBe 3 // cannot customize equality, so fastest to compile, no parentheses required
Come on, your turn: true and false values can be compared with should matchers
true should be(res0)
Booleans in asserts can test equality.
val v1 = 4 v1 shouldEqual res0
Sometimes we expect you to fill in the values
assert(res0 == 1 + 1)