[Gradle] Add tests for KotlinPluginLifecycle.Stage utils

^KT-34662 Verification Pending

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPluginLifecycle.kt

@@ -305,9 +305,11 @@ internal interface KotlinPluginLifecycle {
         val previousOrNull: Stage? get() = values.getOrNull(ordinal - 1)
         val nextOrNull: Stage? get() = values.getOrNull(ordinal + 1)
         val nextOrLast: Stage get() = nextOrNull ?: values.last()
-        val nextOrThrow: Stage get() = values[ordinal + 1]
+        val nextOrThrow: Stage
+            get() = nextOrNull ?: throw IllegalArgumentException("'$this' does not have a next ${Stage::class.simpleName}")
 
         operator fun rangeTo(other: Stage): Set<Stage> {
+            if (this.ordinal > other.ordinal) return emptySet()
             return values.subList(this.ordinal, other.ordinal + 1).toSet()
         }
 

libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/unitTests/KotlinPluginLifecycleTest.kt

@@ -349,4 +349,30 @@ class KotlinPluginLifecycleTest {
             }
         }
     }
+
+    @Test
+    fun `test - Stage - previous next utils`() {
+        assertNull(Stage.values.first().previousOrNull)
+        assertEquals(Stage.values.first(), Stage.values.first().previousOrFirst)
+
+        assertNull(Stage.values.last().nextOrNull)
+        assertEquals(Stage.values.last(), Stage.values.last().nextOrLast)
+
+        assertFailsWith<IllegalArgumentException> { Stage.values.last().nextOrThrow }
+    }
+
+    @Test
+    fun `test - Stage - range utils`() {
+        assertEquals(setOf(BeforeFinaliseDsl, FinaliseDsl, AfterFinaliseDsl), BeforeFinaliseDsl..AfterFinaliseDsl)
+        assertEquals(emptySet(), AfterFinaliseDsl..BeforeFinaliseDsl)
+        assertEquals(setOf(BeforeFinaliseDsl), BeforeFinaliseDsl..BeforeFinaliseDsl)
+
+        assertTrue(FinaliseDsl in Stage.upTo(FinaliseDsl))
+        assertTrue(Stage.values.first() in Stage.upTo(FinaliseDsl))
+        assertTrue(BeforeFinaliseDsl in Stage.upTo(FinaliseDsl))
+        assertTrue(FinaliseDsl.nextOrThrow !in Stage.upTo(FinaliseDsl))
+
+        assertTrue(FinaliseDsl !in Stage.until(FinaliseDsl))
+        assertTrue(FinaliseDsl.previousOrFirst in Stage.until(FinaliseDsl))
+    }
 }