[Commonizer] Implement ReturnTypeNullabilityCommonizationTest

^KT-48567

native/commonizer/tests/org/jetbrains/kotlin/commonizer/hierarchical/ReturnTypeNullabilityCommonizationTest.kt

@@ -0,0 +1,262 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.commonizer.hierarchical
+
+import org.jetbrains.kotlin.commonizer.AbstractInlineSourcesCommonizationTest
+import org.jetbrains.kotlin.commonizer.assertCommonized
+
+class ReturnTypeNullabilityCommonizationTest : AbstractInlineSourcesCommonizationTest() {
+
+    fun `test two nullable functions`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget("a", "fun x(): Any?")
+            simpleSingleSourceTarget("b", "fun x(): Any?")
+        }
+
+        result.assertCommonized("(a, b)", "expect fun x(): Any?")
+    }
+
+    fun `test two non-nullable functions`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget("a", "fun x(): Any")
+            simpleSingleSourceTarget("b", "fun x(): Any")
+        }
+
+        result.assertCommonized("(a, b)", "expect fun x(): Any")
+    }
+
+    fun `test nullable and non-nullable function`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget("a", "fun x(): Any?")
+            simpleSingleSourceTarget("b", "fun x(): Any")
+        }
+
+        result.assertCommonized("(a, b)", "expect fun x(): Any?")
+    }
+
+    fun `test two nullable properties`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget("a", "val x: Any? = Unit")
+            simpleSingleSourceTarget("b", "val x: Any? = Unit")
+        }
+
+        result.assertCommonized("(a, b)", "expect val x: Any?")
+    }
+
+    fun `test two non-nullable properties`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget("a", "val x: Any = Unit")
+            simpleSingleSourceTarget("b", "val x: Any = Unit")
+        }
+
+        result.assertCommonized("(a, b)", "expect val x: Any")
+    }
+
+    fun `test nullable and non-nullable - property`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget("a", "val x: Any? = Unit?")
+            simpleSingleSourceTarget("b", "val x: Any = Unit")
+        }
+
+        result.assertCommonized("(a, b)", "expect val x: Any?")
+    }
+
+
+    fun `test different nullability typealias  - function`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget(
+                "a", """
+                    typealias X = Any?
+                    fun x(): X
+                """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "b", """
+                    typealias X = Any
+                    fun x(): X
+                """.trimIndent()
+            )
+        }
+
+        result.assertCommonized(
+            "(a, b)", """
+                expect class X
+                expect fun x(): X
+            """.trimIndent()
+        )
+    }
+
+    fun `test different nullability typealias chain - function`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget(
+                "a", """
+                    typealias Z = Any
+                    typealias Y = Z?
+                    typealias X = Y
+                    fun x(): X
+                """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "b", """
+                    typealias Z = Any
+                    typealias Y = Z
+                    typealias X = Y
+                    fun x(): X
+                """.trimIndent()
+            )
+        }
+
+        result.assertCommonized(
+            "(a, b)", """
+                typealias Z = Any
+                expect class Y
+                expect class X
+                fun x(): X
+            """.trimIndent()
+        )
+    }
+
+    fun `test different nullability typealias chain - property`() {
+        val result = commonize {
+            outputTarget("(a, b)")
+            simpleSingleSourceTarget(
+                "a", """
+                    typealias Z = Any
+                    typealias Y = Z?
+                    typealias X = Y
+                    val x: X = Unit
+                """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "b", """
+                    typealias Z = Any
+                    typealias Y = Z
+                    typealias X = Y
+                    val x: X = Any
+                """.trimIndent()
+            )
+        }
+
+        result.assertCommonized(
+            "(a, b)", """
+                typealias Z = Any
+                expect class Y
+                expect class X
+                expect val x: X
+            """.trimIndent()
+        )
+    }
+
+
+    fun `test property - hierarchically`() {
+        val result = commonize {
+            outputTarget("(a, b)", "(c, d)", "(a, b, c, d)")
+            "a" withSource "val x: Any? = null"
+            "b" withSource "val x: Any = Unit"
+            "c" withSource "val x: Any = Unit"
+            "d" withSource "val x: Any = Unit"
+        }
+
+        result.assertCommonized("(a, b)", "expect val x: Any?")
+        result.assertCommonized("(c, d)", "expect val x: Any")
+        result.assertCommonized("(a, b, c, d)", "expect val x: Any?")
+    }
+
+    fun `test member - property - hierarchically`() {
+        val result = commonize {
+            outputTarget("(a, b)", "(c, d)", "(a, b, c, d)")
+
+            simpleSingleSourceTarget(
+                "a", """
+                class X {
+                    val x: Any?
+                }
+            """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "b", """
+                class X {
+                    val x: Any
+                }
+            """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "c", """
+                class X {
+                    val x: Any
+                }
+            """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "d", """
+                class X {
+                    val x: Any
+                }
+            """.trimIndent()
+            )
+        }
+
+        result.assertCommonized("(a, b)", """expect class X()""")
+        result.assertCommonized("(c, d)", """expect class X() { expect val x: Any }""")
+        result.assertCommonized("(a, b, c, d)", """expect class X()""")
+    }
+
+    fun `test member - function - hierarchically`() {
+        val result = commonize {
+            outputTarget("(a, b)", "(c, d)", "(a, b, c, d)")
+
+            simpleSingleSourceTarget(
+                "a", """
+                class X {
+                    fun x(): Any?
+                }
+            """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "b", """
+                class X {
+                    fun x(): Any
+                }
+            """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "c", """
+                class X {
+                   fun x(): Any
+                }
+            """.trimIndent()
+            )
+
+            simpleSingleSourceTarget(
+                "d", """
+                class X {
+                    fun x(): Any
+                }
+            """.trimIndent()
+            )
+        }
+
+        result.assertCommonized("(a, b)", """expect class X()""")
+        result.assertCommonized("(c, d)", """expect class X() { expect fun x(): Any }""")
+        result.assertCommonized("(a, b, c, d)", """expect class X()""")
+    }
+}