#86 - Add non-nullable variant to RowsFetchSpec extensions.

This commit is a follow-up of gh-63.

Original pull request: #86.

Author: sdeleuze

src/main/kotlin/org/springframework/data/r2dbc/function/RowsFetchSpecExtensions.kt

@@ -16,22 +16,39 @@
 package org.springframework.data.r2dbc.function
 
 import kotlinx.coroutines.reactive.awaitFirstOrNull
+import kotlinx.coroutines.reactive.awaitSingle
 
 /**
- * Coroutines variant of [RowsFetchSpec.one].
+ * Non-nullable Coroutines variant of [RowsFetchSpec.one].
  *
  * @author Sebastien Deleuze
  */
-suspend fun <T> RowsFetchSpec<T>.awaitOne(): T?
+suspend fun <T> RowsFetchSpec<T>.awaitOne(): T
+		= one().awaitSingle()
+
+/**
+ * Nullable Coroutines variant of [RowsFetchSpec.one].
+ *
+ * @author Sebastien Deleuze
+ */
+suspend fun <T> RowsFetchSpec<T>.awaitOneOrNull(): T?
         = one().awaitFirstOrNull()
 
 /**
- * Coroutines variant of [RowsFetchSpec.first].
+ * Non-nullable Coroutines variant of [RowsFetchSpec.first].
+ *
+ * @author Sebastien Deleuze
+ */
+suspend fun <T> RowsFetchSpec<T>.awaitFirst(): T
+        = first().awaitSingle()
+
+/**
+ * Nullable Coroutines variant of [RowsFetchSpec.first].
  *
  * @author Sebastien Deleuze
  */
-suspend fun <T> RowsFetchSpec<T>.awaitFirst(): T?
-        = first().awaitFirstOrNull()
+suspend fun <T> RowsFetchSpec<T>.awaitFirstOrNull(): T?
+		= first().awaitFirstOrNull()
 
 // TODO Coroutines variant of [RowsFetchSpec.all], depends on [kotlinx.coroutines#254](https://github.com/Kotlin/kotlinx.coroutines/issues/254).
 // suspend fun <T> RowsFetchSpec<T>.awaitAll() = all()...

src/test/kotlin/org/springframework/data/r2dbc/function/RowsFetchSpecExtensionsTests.kt

@@ -20,8 +20,10 @@ import io.mockk.mockk
 import io.mockk.verify
 import kotlinx.coroutines.runBlocking
 import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatExceptionOfType
 import org.junit.Test
 import reactor.core.publisher.Mono
+import java.lang.NullPointerException
 
 /**
  * Unit tests for [RowsFetchSpec] extensions.
@@ -31,7 +33,7 @@ import reactor.core.publisher.Mono
 class RowsFetchSpecExtensionsTests {
 
 	@Test // gh-63
-	fun awaitOne() {
+	fun awaitOneWithValue() {
 
 		val spec = mockk<RowsFetchSpec<String>>()
 		every { spec.one() } returns Mono.just("foo")
@@ -46,7 +48,52 @@ class RowsFetchSpecExtensionsTests {
 	}
 
 	@Test // gh-63
-	fun awaitFirst() {
+	fun awaitOneWithNull() {
+
+		val spec = mockk<RowsFetchSpec<String>>()
+		every { spec.one() } returns Mono.empty()
+
+		assertThatExceptionOfType(NoSuchElementException::class.java).isThrownBy {
+			runBlocking { spec.awaitOne() }
+		}
+
+		verify {
+			spec.one()
+		}
+	}
+
+	@Test // gh-63
+	fun awaitOneOrNullWithValue() {
+
+		val spec = mockk<RowsFetchSpec<String>>()
+		every { spec.one() } returns Mono.just("foo")
+
+		runBlocking {
+			assertThat(spec.awaitOneOrNull()).isEqualTo("foo")
+		}
+
+		verify {
+			spec.one()
+		}
+	}
+
+	@Test // gh-63
+	fun awaitOneOrNullWithNull() {
+
+		val spec = mockk<RowsFetchSpec<String>>()
+		every { spec.one() } returns Mono.empty()
+
+		runBlocking {
+			assertThat(spec.awaitOneOrNull()).isNull()
+		}
+
+		verify {
+			spec.one()
+		}
+	}
+
+	@Test // gh-63
+	fun awaitFirstWithValue() {
 
 		val spec = mockk<RowsFetchSpec<String>>()
 		every { spec.first() } returns Mono.just("foo")
@@ -59,4 +106,49 @@ class RowsFetchSpecExtensionsTests {
 			spec.first()
 		}
 	}
+
+	@Test // gh-63
+	fun awaitFirstWithNull() {
+
+		val spec = mockk<RowsFetchSpec<String>>()
+		every { spec.first() } returns Mono.empty()
+
+		assertThatExceptionOfType(NoSuchElementException::class.java).isThrownBy {
+			runBlocking { spec.awaitFirst() }
+		}
+
+		verify {
+			spec.first()
+		}
+	}
+
+	@Test // gh-63
+	fun awaitFirstOrNullWithValue() {
+
+		val spec = mockk<RowsFetchSpec<String>>()
+		every { spec.first() } returns Mono.just("foo")
+
+		runBlocking {
+			assertThat(spec.awaitFirstOrNull()).isEqualTo("foo")
+		}
+
+		verify {
+			spec.first()
+		}
+	}
+
+	@Test // gh-63
+	fun awaitFirstOrNullWithNull() {
+
+		val spec = mockk<RowsFetchSpec<String>>()
+		every { spec.first() } returns Mono.empty()
+
+		runBlocking {
+			assertThat(spec.awaitFirstOrNull()).isNull()
+		}
+
+		verify {
+			spec.first()
+		}
+	}
 }