[LL] Add test for KmpModuleSorter

KTIJ-27569

analysis/analysis-test-framework/tests/org/jetbrains/kotlin/analysis/test/framework/TestWithMockProject.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2023 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.analysis.test.framework
+
+import com.intellij.mock.MockProject
+import com.intellij.openapi.project.Project
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeEach
+
+/**
+ * Note that the project created by this class is a completely non-functional stub.
+ * It is only useful in tests that don't depend on Project's functionality.
+ */
+abstract class TestWithMockProject : TestWithDisposable() {
+    private var _project: Project? = null
+    protected val project: Project get() = _project!!
+
+    @BeforeEach
+    fun initProject() {
+        _project = MockProject(null, disposable)
+    }
+
+    @AfterEach
+    fun cleanup() {
+        _project = null
+    }
+}

analysis/analysis-test-framework/tests/org/jetbrains/kotlin/analysis/test/framework/project/structure/KtSourceModuleImpl.kt

@@ -25,4 +25,8 @@ class KtSourceModuleImpl(
     override val directRegularDependencies: MutableList<KtModule> = mutableListOf()
     override val directDependsOnDependencies: MutableList<KtModule> = mutableListOf()
     override val directFriendDependencies: MutableList<KtModule> = mutableListOf()
+
+    override fun toString(): String {
+        return moduleName
+    }
 }

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/sessions/LLFirAbstractSessionFactory.kt

@@ -609,6 +609,7 @@ internal abstract class LLFirAbstractSessionFactory(protected val project: Proje
             }
         }
 
+        // Please update KmpModuleSorterTest#buildDependenciesToTest if the logic of collecting dependencies changes
         val dependencyModules = buildSet {
             addAll(module.directRegularDependencies)
 

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/KmpModuleSorterTest.kt

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2010-2023 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.analysis.low.level.api.fir
+
+import com.intellij.psi.search.GlobalSearchScope
+import org.jetbrains.kotlin.analysis.low.level.api.fir.providers.KmpModuleSorter
+import org.jetbrains.kotlin.analysis.project.structure.KtModule
+import org.jetbrains.kotlin.analysis.test.framework.TestWithMockProject
+import org.jetbrains.kotlin.analysis.test.framework.project.structure.KtSourceModuleImpl
+import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
+import org.jetbrains.kotlin.platform.CommonPlatforms
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+
+class KmpModuleSorterTest : TestWithMockProject() {
+    @Test
+    fun testNonKmpDependencies() {
+        val a = createKtModule("A")
+        val b = createKtModule("B")
+        val c = createKtModule("C")
+        val d = createKtModule("D", directRegularDependencies = listOf(a, b, c))
+        assertEquals(listOf(a, b, c), buildDependenciesToTest(d))
+    }
+
+    @Test
+    fun testOnlyKmpDependencies() {
+        val p1CommonMain = createKtModule("p1.commonMain")
+        val p1NativeMain = createKtModule("p1.nativeMain", directDependsOnDependencies = listOf(p1CommonMain))
+        val p1IosMain = createKtModule("p1.iosMain", directDependsOnDependencies = listOf(p1NativeMain))
+        val p2IosMain = createKtModule("p2.iosMain", directRegularDependencies = listOf(p1CommonMain, p1NativeMain, p1IosMain))
+
+        assertEquals(listOf(p1IosMain, p1NativeMain, p1CommonMain), buildDependenciesToTest(p2IosMain))
+    }
+
+    @Test
+    fun testMixedKmpAndUsualDependenciesShuffled() {
+        val a = createKtModule("A")
+        val b1 = createKtModule("B1")
+        val b2 = createKtModule("B2", directDependsOnDependencies = listOf(b1))
+        val b3 = createKtModule("B3", directDependsOnDependencies = listOf(b2))
+        val c = createKtModule("C")
+        val d1 = createKtModule("D1")
+        val d2 = createKtModule("D2", directDependsOnDependencies = listOf(d1))
+
+        val p2IosMain = createKtModule(
+            "p2.iosMain", directRegularDependencies = listOf(
+                a, b2, c, b1, d2, b3, d1
+            )
+        )
+
+        assertEquals(listOf(a, b3, c, b2, d2, b1, d1), this.buildDependenciesToTest(p2IosMain))
+    }
+
+    @Test
+    fun testDependsOnDependenciesFromSelfAndOtherProject() {
+        val p1Common = createKtModule("p1.common")
+        val p1Intermediate = createKtModule("p1.intermediate", directDependsOnDependencies = listOf(p1Common))
+        val p1Platform = createKtModule("p1.platform", directDependsOnDependencies = listOf(p1Intermediate))
+        val p2Common = createKtModule("p2.common", directRegularDependencies = listOf(p1Common))
+        val p2Intermediate = createKtModule(
+            "p2.intermediate",
+            directDependsOnDependencies = listOf(p2Common),
+            directRegularDependencies = listOf(p1Common, p1Intermediate),
+        )
+        val p2Platform = createKtModule(
+            "p2.platform",
+            directDependsOnDependencies = listOf(p2Intermediate),
+            directRegularDependencies = listOf(p1Common, p1Intermediate, p1Platform)
+        )
+
+        assertEquals(listOf(p1Common), this.buildDependenciesToTest(p2Common))
+        assertEquals(listOf(p1Intermediate, p1Common, p2Common), this.buildDependenciesToTest(p2Intermediate))
+        assertEquals(listOf(p1Platform, p1Intermediate, p1Common, p2Intermediate, p2Common), this.buildDependenciesToTest(p2Platform))
+    }
+
+    // See [org.jetbrains.kotlin.analysis.low.level.api.fir.sessions.LLFirAbstractSessionFactory#collectDependencySymbolProviders]
+    private fun buildDependenciesToTest(module: KtModule): List<KtModule> {
+        val dependenciesToSort = buildSet {
+            addAll(module.directRegularDependencies)
+            addAll(module.transitiveDependsOnDependencies)
+        }
+        return KmpModuleSorter.order(dependenciesToSort.toList())
+    }
+
+    private fun createKtModule(
+        name: String,
+        directRegularDependencies: List<KtModule> = emptyList(),
+        directDependsOnDependencies: List<KtModule> = emptyList(),
+        directFriendDependencies: List<KtModule> = emptyList(),
+    ): KtModule {
+        return KtSourceModuleImpl(
+            name, CommonPlatforms.defaultCommonPlatform, LanguageVersionSettingsImpl.DEFAULT, project, GlobalSearchScope.EMPTY_SCOPE
+        ).apply {
+            this.directRegularDependencies.addAll(directRegularDependencies)
+            this.directFriendDependencies.addAll(directFriendDependencies)
+            this.directDependsOnDependencies.addAll(directDependsOnDependencies)
+        }
+    }
+}