doc / ch.tutteli.atrium.creating / SubjectProvider / subject

subject

abstract val subject: T
Deprecated: Switch from Assert to Expect and do no longer access subject as it might break reporting. In contexts where it is safe to access the subject, it is passed by parameter and can be accessed via `it`. See KDoc for migration hints; will be removed with 1.0.0

The subject of an Assertion -- deprecated, will be removed with 1.0.0.

Accessing the subject in places which are not safe for reporting breaks reporting and can hinder that all assertions can be evaluated. For instance:

expect(person).isA<Student> { // is not a student -> subject is now undefined, throws PlantHasNoSubjectException if accessed
  property(subject::firstName).toBe("Robert")
  property(Person::lastName).toBe("Stoll") // is not evaluated as subject one line above already threw PlantHasNoSubjectException
}

For this reason we refactored our design and now pass subject as arguments in places where you need it and where it is safe to use it.

It's best if you switch entirely from Assert to Expect and from AssertImpl to ExpectImpl. Have a look at the migration guide given in https://github.com/robstoll/atrium/releases/tag/v0.9.0#migration for a fast way to migrate everything.

In case you want to migrate part by part then the following, non-exhaustive list, tries to explain how you need to migrate to use the new design:

  1.  fun Assert<Int>.isEven() = createAndAddAssertion(IS, Text("even")) { subject % 2 == 0 }  // old
        fun Expect<Int>.isEven() = createAndAddAssertion(IS, Text("even")) { it % 2 == 0 }       // new
    

    notice the switch from Assert to Expect

  2.  AssertImpl.builder.createDescriptive(TO_BE, expected) { subject == expected }   // old
        AssertImpl.builder.createDescriptive(this, TO_BE, expected) { it == expected }  // new
    
  3.  AssertImpl.builder.descriptive.withTest { subject == expected }   // old
        AssertImpl.builder.descriptive.withTest(this) { it == expected }  // new - `this` refers to Assert or Expect
    
  4.  AssertImpl.builder.descriptive.withTest(...).withFailureHint { ...  subject ... }   // old
        AssertImpl.builder.descriptive.withTest(...).withFailureHint(this) { ... it ... }  // new - `this` refers to Assert or Expect
    
  5.  AssertImpl.builder.descriptive.withTest(...).withFailureHint(...).showOnlyIf { ... subject ... }   // old
        AssertImpl.builder.descriptive.withTest(...).withFailureHint(...).showOnlyIf(this) { ... it ... }  // new - `this` refers to Assert or Expect
    
  6.  AssertImpl.changeSubject(this) { subject.asIterable() }        // old
        ExpectImpl.changeSubject(this).unreported { it.asIterable() }  // new
    

    notice the switch from AssertImpl to ExpectImpl

  7. Feature assertions Those are not straight forward and require that you migrate to Expect first or that you use asExpect

     import ch.tutteli.atrium.verbs.expect
        expect(person) {
          property(subject::firstName).startsWith("hello")
          returnValueOf(subject::myFun, "arg1").toBe(42)
        } and {
          property(subject::lastName).toBe("world")
        }
    
        // using asExpect
    
        expect(person).asExpect { // everything within the brackets is in the Expect world
          feature { f(it::firstName) }.startsWith("hello")
          feature { f(it::myFun, "arg1") }.toBe(42)
        }    // back to the Assert world
        .and {
          asExpect() // switch to Expect world, all subsequent calls in Expect world
            .feature{ f(subject::lastName) }
            .toBe("world")
        }
    

    Have a look at the migration guides if you want to switch entirely to Expect as there is a fast search & replace strategy.

  8. nested expect, assert or assertThat

     //old
        expect(1 to 2) {
          expect(subject.second).toBe(2)
        }
    
        //new
        expect(1 to 2) {
          feature { f(it::second) }.toBe(2)
        }
    

    same same but different for assert and assertThat