can find pedigree under all basic conditions

composeApp/src/commonMain/kotlin/model/visitors/PedigreeFinder.kt

@@ -3,24 +3,24 @@ package model.visitors
 import model.Item
 
 class PedigreeFinder(val rootItem: Item) {
-    private val familyTree = mutableListOf<Item>()
 
     fun findPedigree(item: Item): List<Item> {
         return if (item == rootItem) {
             listOf(item)
         } else if(rootItem.subItems.isNotEmpty()) {
-            familyTree.add(rootItem)
-            rootItem.subItems.map {
-                PedigreeFinder(it).findPedigree(item)
-            }.filter {
-                it.last() == item
-            }.flatten()
-                .also {
-                    familyTree.addAll(it)
-                }
-            familyTree
+            listOf(rootItem) + findChildToItem(item)
         } else {
             emptyList()
         }
     }
+
+    fun findChildToItem(item: Item): List<Item> {
+        return rootItem.subItems.map {
+            PedigreeFinder(it).findPedigree(item)
+        }.filter {
+            lastItemIsItem(it, item)
+        }.flatten()
+    }
+
+    private fun lastItemIsItem(it: List<Item>, item: Item) = it.isNotEmpty() && it.last() == item
 }

composeApp/src/commonTest/kotlin/model/visitors/PedigreeFinderTest.kt

@@ -51,4 +51,105 @@ class PedigreeFinderTest {
         // Then
         pedigree.shouldContainExactly(root, child)
     }
+
+    @Test
+    fun `looking for pedigree works with multiple children`() {
+        // Given
+        val root = Item("Root")
+        val child1 = Item("Child1")
+        val child2 = Item("Child2")
+        root.add(child1)
+        root.add(child2)
+
+        val finder = PedigreeFinder(root)
+
+        // When
+        val pedigree = finder.findPedigree(child2)
+
+        // Then
+        pedigree.shouldContainExactly(root, child2)
+    }
+
+    @Test
+    fun `looking for pedigree works with multiple generations`() {
+        // Given
+        val root = Item("Root")
+        val child1 = Item("Child1")
+        val child2 = Item("Child2")
+        val grandchild = Item("Grandchild")
+        root.add(child1)
+        root.add(child2)
+        child2.add(grandchild)
+
+        val finder = PedigreeFinder(root)
+
+        // When
+        val pedigree = finder.findPedigree(grandchild)
+
+        // Then
+        pedigree.shouldContainExactly(root, child2, grandchild)
+    }
+
+    @Test
+    fun `looking for pedigree works with multiple generations and multiple children`() {
+        // Given
+        val root = Item("Root")
+        val child1 = Item("Child1")
+        val child2 = Item("Child2")
+        val grandchild1 = Item("Grandchild1")
+        val grandchild2 = Item("Grandchild2")
+        root.add(child1)
+        root.add(child2)
+        child2.add(grandchild1)
+        child2.add(grandchild2)
+
+        val finder = PedigreeFinder(root)
+
+        // When
+        val pedigree = finder.findPedigree(child1)
+
+        // Then
+        pedigree.shouldContainExactly(root, child1)
+    }
+
+    @Test
+    fun `findChildToItem works one level down`() {
+        // Given
+        val root = Item("Root")
+        val child = Item("Child")
+        val grandChild = Item("Grandchild")
+        root.add(child)
+        child.add(grandChild)
+
+        val finder = PedigreeFinder(root)
+
+        // When
+        val pedigree = finder.findChildToItem(grandChild)
+
+        // Then
+        pedigree.shouldContainExactly(child, grandChild)
+    }
+
+    @Test
+    fun `findChildToItem returns empty list if no path`() {
+        // Given
+        val root = Item("Root")
+        val child = Item("Child")
+        val child2 = Item("Child2")
+        val grandchild2 = Item("Grandchild2")
+        val grandChild = Item("Grandchild")
+        root.add(child)
+        root.add(child2)
+        child.add(grandChild)
+        child2.add(grandchild2)
+
+        val finder = PedigreeFinder(child)
+
+        // When
+        val pedigree = finder.findChildToItem(grandchild2)
+
+        // Then
+        pedigree.shouldBeEmpty()
+
+    }
 }