Atrium: shortcut for Optional.get named isPresent

[robstoll]

Platform (JVM and/or JS): JVM (only jdk8)

Code related feature

expect(Optional.of(1)).isPresent().toBe(1)                  // isPresent incorporates check for empty
//instead of
expect(Optional.of(1)).feature(Optional::get).toBe(1) // get throws in case of empty

//and
expect(Optional.of(1)).isPresent {  // isPresent incorporates check for empty
  isGreaterThan(1)
  isLessThan(4)
}
//instead of 
expect(Optional.of(1)).feature(Optional::get) { // get throws in case of empty
  isGreaterThan(1)
  isLessThan(4)
}

In reporting we want to see for

expect(Optional.empty<Int>).isPresent().toBe(1)

the following report:

expect: Optional.empty
◆ ▶ get(): ❗❗is empty

and for

expect(Optional.empty<Int>).isPresent() { toBe(1) }

the following

expect: Optional.empty
◆ ▶ get(): ❗❗is empty
  >> to be: 1

and for

expect(Optional.of(2)).isPresent() { toBe(1) }

the following:

expect: Optional[2]
◆ ▶ get(): 2
   ◾ to be: 1

Following the things you need to do:

lib

• implement _isPresent in optionalAssertions by using the `ExpectImpl.feature.extractor... (see resultAssertions.kt _isSuccess as guideline

domain

• extend OptionalAssertions with a function isPresent which returns ExtractedFeaturePostStep<T, E> where T: Optional<E> (see ResultAssertions.isSucces as a guideline)
• modify OptionalAssertionsBuilder, delegate to optionalAssertions (see ListAssertionsBuilder as a guideline)
• delegate implementation to robstoll-lib in OptionalAssertionsImpl (see ListAssertionsImpl as a guideline)

api

• provide a val which returns Expect<E> (see resultAssertions.kt as a guideline) and add @since 0.9.0 to the KDOC
• provide a fun which expects an assertionCreator lambda and returns Expect<T> (see resultAssertions.kt as a guideline) and @since 0.9.0 (adopt to current version) to the KDOC
• extend OptionalFeatureAssertionsSpec in specs-common (see for instance ListFeatureAssertionsSpec) and extend it in atrium-api-fluent-en_GB-common/src/test

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[jGleitz]

Suggestion: if get would be called toBePresent (without any other change), it would be more obvious that it actually contains an assertion.

[robstoll]

I try to use the same names one is already familiar with for feature extraction, IMO this way we have a more intuitive API than inventing new names. We already have List.get, Throwable.message let's stick with that pattern. We could introduce isPresent in addition though.

[robstoll]

I mulled your input over and I came to the conclusion that get might indeed not be the best choice for the naming. I think isPresent is better as it is an obvious counterpart to isEmpty and many people argue that it is discouraged to use Optional.get (because it throws if empty). Thus I guess those people would look for an isPresent or getOrElse but getOrElse does not make sense in this context.

[byarr]

I'll work on this

[jGleitz]

I think isPresent is better than get. And I think you give good reasons!

[robstoll]

@byarr I have updated the description regarding reporting.

[robstoll]

@byarr do you need help?

[byarr]

@robstoll Sorry, I did take quick look at this. But I havnt really got the time right now. Unassigning myself.

[robstoll]

@byarr no problem if you need longer, just wanted to make sure you are not stuck. Rich out here if you want to take it over again and I re-assign it to you.

[slalu]

I'll work on this.

In the description, you mention "ExtractedFeatureOption" but I don't find this class. I assumed it was ExtractedFeaturePostStep when I looked at the examples provided. Am I right or I am missing something?

[robstoll]

That's correct. The class was renamed since I created this issue

[robstoll]

implemented with 8cd76f3