From 1d11412b481617e58843898dc77a797b794ef712 Mon Sep 17 00:00:00 2001
From: Douglas Ronne <vextorspace@gmail.com>
Date: Sat, 13 Jul 2024 12:31:45 -0400
Subject: [PATCH] added guarding test to make sure no triversing back up tree
 in visitor

---
 .../commonMain/kotlin/model/ItemVisitor.kt    |  8 +++
 .../kotlin/model/ItemVisitorAction.kt         |  5 ++
 .../kotlin/model/ItemVisitorCollector.kt      | 10 ++++
 .../model/ItemVisitorVisitsAllSubItemsTest.kt | 49 +++++++++++++++++++
 4 files changed, 72 insertions(+)
 create mode 100644 composeApp/src/commonMain/kotlin/model/ItemVisitor.kt
 create mode 100644 composeApp/src/commonMain/kotlin/model/ItemVisitorAction.kt
 create mode 100644 composeApp/src/commonTest/kotlin/model/ItemVisitorCollector.kt
 create mode 100644 composeApp/src/commonTest/kotlin/model/ItemVisitorVisitsAllSubItemsTest.kt

diff --git a/composeApp/src/commonMain/kotlin/model/ItemVisitor.kt b/composeApp/src/commonMain/kotlin/model/ItemVisitor.kt
new file mode 100644
index 0000000..1c7f741
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/model/ItemVisitor.kt
@@ -0,0 +1,8 @@
+package model
+
+class ItemVisitor(val action: ItemVisitorAction) {
+    fun visit(item: Item) {
+        action.accept(item)
+        item.subItems.forEach { visit(it) }
+    }
+}
diff --git a/composeApp/src/commonMain/kotlin/model/ItemVisitorAction.kt b/composeApp/src/commonMain/kotlin/model/ItemVisitorAction.kt
new file mode 100644
index 0000000..96b365f
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/model/ItemVisitorAction.kt
@@ -0,0 +1,5 @@
+package model
+
+interface ItemVisitorAction {
+    fun accept(item: Item)
+}
diff --git a/composeApp/src/commonTest/kotlin/model/ItemVisitorCollector.kt b/composeApp/src/commonTest/kotlin/model/ItemVisitorCollector.kt
new file mode 100644
index 0000000..732acf9
--- /dev/null
+++ b/composeApp/src/commonTest/kotlin/model/ItemVisitorCollector.kt
@@ -0,0 +1,10 @@
+package model
+
+class ItemVisitorCollector : ItemVisitorAction {
+    val items = mutableListOf<Item>()
+
+    override fun accept(item: Item) {
+        items.add(item)
+    }
+
+}
diff --git a/composeApp/src/commonTest/kotlin/model/ItemVisitorVisitsAllSubItemsTest.kt b/composeApp/src/commonTest/kotlin/model/ItemVisitorVisitsAllSubItemsTest.kt
new file mode 100644
index 0000000..61753ef
--- /dev/null
+++ b/composeApp/src/commonTest/kotlin/model/ItemVisitorVisitsAllSubItemsTest.kt
@@ -0,0 +1,49 @@
+package model
+
+import io.kotest.matchers.collections.shouldContainExactlyInAnyOrder
+import kotlin.test.Test
+
+class ItemVisitorVisitsAllSubItemsTest {
+
+    @Test
+    fun `ItemVisitor visits all sub items`() {
+        // Given
+        val item = Item("parent")
+        val child = Item("child")
+        val sibling = Item("sibling")
+        val grandChild = Item("grandChild")
+        child.add(grandChild)
+        item.add(child)
+        item.add(sibling)
+
+        val itemCollector = ItemVisitorCollector()
+        val visitor = ItemVisitor(itemCollector)
+
+        // When
+        visitor.visit(item)
+
+        // Then
+        itemCollector.items shouldContainExactlyInAnyOrder  listOf(item, child, sibling, grandChild)
+    }
+
+    @Test
+    fun `ItemVisitor starting at child does not get other branches`() {
+        // Given
+        val item = Item("parent")
+        val child = Item("child")
+        val sibling = Item("sibling")
+        val grandChild = Item("grandChild")
+        child.add(grandChild)
+        item.add(child)
+        item.add(sibling)
+
+        val itemCollector = ItemVisitorCollector()
+        val visitor = ItemVisitor(itemCollector)
+
+        // When
+        visitor.visit(child)
+
+        // Then
+        itemCollector.items shouldContainExactlyInAnyOrder  listOf(child, grandChild)
+    }
+}
\ No newline at end of file