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Add Result#orElseThrow

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This commit is contained in:
Michael Bull 2021-10-26 15:51:56 +01:00
parent 419927f098
commit f236e2674b
2 changed files with 84 additions and 44 deletions
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10
kotlin-result/src/commonMain/kotlin/com/github/michaelbull/result/Or.kt
View File

@ -41,6 +41,16 @@ public inline infix fun <V, E> Result<V, E>.orElse(transform: (E) -> Result<V, E
}
}
/**
* Throws the [error][Err.error] if this [Result] is [Err], otherwise returns this [Ok].
*/
public fun <V, E : Throwable> Result<V, E>.orElseThrow(): Ok<V> {
return when (this) {
is Ok -> this
is Err -> throw error
}
}
/**
* Returns the [transformation][transform] of the [error][Err.error] if this [Result] is [Err],
* otherwise this [Ok].

118
kotlin-result/src/commonTest/kotlin/com/github/michaelbull/result/OrTest.kt
View File

@ -2,6 +2,7 @@ package com.github.michaelbull.result
import kotlin.test.Test
import kotlin.test.assertEquals
import kotlin.test.assertFailsWith
class OrTest {
private object OrError
@ -42,20 +43,41 @@ class OrTest {
}
}
class OrElseThrow {
@Test
fun returnsValueIfOk() {
assertEquals(
expected = Ok(5000),
actual = Ok(5000).orElseThrow()
)
}
@Test
fun returnsTransformedValueIfErr() {
val error = RuntimeException("or else throw")
fun provideError(): Result<String, Throwable> {
return Err(error)
}
assertFailsWith<RuntimeException>(error.message, provideError()::orElseThrow)
}
}
class Recover {
@Test
fun returnsValueIfOk() {
assertEquals(
expected = 3000,
actual = Ok(3000).recover { 4000 }.get()
expected = Ok(3000),
actual = Ok(3000).recover { 4000 }
)
}
@Test
fun returnsTransformedValueIfErr() {
assertEquals(
expected = 2000,
actual = Err(4000).recover { 2000 }.get()
expected = Ok(2000),
actual = Err(4000).recover { 2000 }
)
}
}
@ -63,45 +85,49 @@ class OrTest {
class RecoverIf {
@Test
fun returnsValueIfOk() {
fun predicate(int: Int): Boolean {
return int == 4000
}
assertEquals(
expected = 3000,
actual = (Ok(3000) as Result<Int, Int>).recoverIf(
{ it == 4000 },
{ 2000 }
).get()
expected = Ok(3000),
actual = Ok(3000).recoverIf(::predicate) { 2000 }
)
}
@Test
fun returnsTransformedErrorAsOkIfErrAndPredicateMatch() {
fun predicate(int: Int): Boolean {
return int == 4000
}
assertEquals(
expected = 2000,
actual = Err(4000).recoverIf(
{ it == 4000 },
{ 2000 }
).get()
expected = Ok(2000),
actual = Err(4000).recoverIf(::predicate) { 2000 }
)
}
@Test
fun doesNotReturnTransformedErrorAsOkIfErrAndPredicateDoesNotMatch() {
fun predicate(int: Int): Boolean {
return int == 3000
}
assertEquals(
expected = null,
actual = Err(4000).recoverIf(
{ it == 3000 },
{ 2000 }
).get()
expected = Err(4000),
actual = Err(4000).recoverIf(::predicate) { 2000 }
)
}
@Test
fun returnErrIfErrAndPredicateDoesNotMatch() {
fun predicate(int: Int): Boolean {
return int == 3000
}
assertEquals(
expected = 4000,
actual = Err(4000).recoverIf(
{ it == 3000 },
{ 2000 }
).getError()
expected = Err(4000),
actual = Err(4000).recoverIf(::predicate) { 2000 }
)
}
}
@ -109,45 +135,49 @@ class OrTest {
class RecoverUnless {
@Test
fun returnsValueIfOk() {
fun predicate(int: Int): Boolean {
return int == 4000
}
assertEquals(
expected = 3000,
actual = (Ok(3000) as Result<Int, Int>).recoverUnless(
{ it == 4000 },
{ 2000 }
).get()
expected = Ok(3000),
actual = Ok(3000).recoverUnless(::predicate) { 2000 }
)
}
@Test
fun returnsTransformedErrorAsOkIfErrAndPredicateDoesNotMatch() {
fun predicate(int: Int): Boolean {
return int == 3000
}
assertEquals(
expected = 2000,
actual = Err(4000).recoverUnless(
{ it == 3000 },
{ 2000 }
).get()
expected = Ok(2000),
actual = Err(4000).recoverUnless(::predicate) { 2000 }
)
}
@Test
fun doesNotReturnTransformedErrorAsOkIfErrAndPredicateMatches() {
fun predicate(int: Int): Boolean {
return int == 4000
}
assertEquals(
expected = null,
actual = Err(4000).recoverUnless(
{ it == 4000 },
{ 2000 }
).get()
expected = Err(4000),
actual = Err(4000).recoverUnless(::predicate) { 2000 }
)
}
@Test
fun returnErrIfErrAndPredicateDoesMatch() {
fun predicate(int: Int): Boolean {
return int == 4000
}
assertEquals(
expected = 4000,
actual = Err(4000).recoverUnless(
{ it == 4000 },
{ 2000 }
).getError()
expected = Err(4000),
actual = Err(4000).recoverUnless(::predicate) { 2000 }
)
}
}