implement first test search, just a simple num game and fix all the i…

…ssues that were found on the way

build.gradle.kts

@@ -1,18 +1,22 @@
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
-    kotlin("jvm") version "1.2.60"
+    kotlin("jvm") version "1.3.0"
 }
 
 group = "io.dkozak"
 version = "1.0-SNAPSHOT"
 
+val junitVersion = "5.3.1"
+
 repositories {
     mavenCentral()
 }
 
 dependencies {
     compile(kotlin("stdlib-jdk8"))
+    compile("org.junit.jupiter:junit-jupiter-api:$junitVersion")
+    compile("org.junit.jupiter:junit-jupiter-engine:$junitVersion")
 }
 
 tasks.withType<KotlinCompile> {

src/main/io/dkozak/search/engine/engine.kt

@@ -4,9 +4,9 @@ import io.dkozak.search.model.EngineConfiguration
 import io.dkozak.search.model.Node
 
 
-fun search(engineConfiguration: EngineConfiguration, logger: (String) -> Unit = {}) = engineConfiguration.executeSearch(logger)
+fun <NodeType : Node> search(engineConfiguration: EngineConfiguration<NodeType>, logger: (String) -> Unit = {}) = engineConfiguration.executeSearch(logger)
 
-private fun EngineConfiguration.executeSearch(logger: (String) -> Unit): Node? {
+private fun <NodeType : Node> EngineConfiguration<NodeType>.executeSearch(logger: (String) -> Unit): Node? {
     val queue = searchQueue
     queue.addNode(initialState)
     while (!queue.isEmpty()) {

src/main/io/dkozak/search/model/EngineConfiguration.kt

@@ -1,10 +1,10 @@
 package io.dkozak.search.model
 
-class EngineConfiguration
+class EngineConfiguration<NodeType : Node>
 (
-        val initialState: Node,
-        val searchQueue: SearchQueue,
-        val expandNode: (Node) -> List<Node>,
-        val nodeFilter: (Node) -> Boolean,
-        val isFinalState: (Node) -> Boolean
+        val initialState: NodeType,
+        val searchQueue: SearchQueue<NodeType>,
+        val expandNode: (NodeType) -> List<NodeType>,
+        val nodeFilter: (NodeType) -> Boolean,
+        val isFinalState: (NodeType) -> Boolean
 )

src/main/io/dkozak/search/model/QueueBasedSearchQueue.kt

@@ -0,0 +1,13 @@
+package io.dkozak.search.model
+
+import java.util.*
+
+class QueueBasedSearchQueue<NodeType : Node> : SearchQueue<NodeType> {
+    private val queue: Deque<NodeType> = LinkedList()
+
+    override fun next(): NodeType = queue.poll()
+
+    override fun addNodes(nodes: List<NodeType>) = nodes.forEach { queue.addLast(it) }
+
+    override fun isEmpty(): Boolean = queue.isEmpty()
+}

src/main/io/dkozak/search/model/SearchQueue.kt

@@ -1,9 +1,9 @@
 package io.dkozak.search.model
 
-interface SearchQueue {
-    fun next(): Node
-    fun addNodes(nodes: List<Node>)
+interface SearchQueue<NodeType : Node> {
+    fun next(): NodeType
+    fun addNodes(nodes: List<NodeType>)
     fun isEmpty(): Boolean
 
-    fun addNode(node: Node) = addNodes(listOf(node))
+    fun addNode(node: NodeType) = addNodes(listOf(node))
 }

src/test/io/dkozak/search/engine/EngineTest.kt

@@ -0,0 +1,24 @@
+package io.dkozak.search.engine
+
+import io.dkozak.search.model.EngineConfiguration
+import io.dkozak.search.model.Node
+import io.dkozak.search.model.QueueBasedSearchQueue
+import org.junit.jupiter.api.Test
+
+data class NumNode(val num: Int) : Node
+
+class EngineTest {
+
+    @Test
+    fun `simpleNumberGame solution should be found`() {
+        val configuration = EngineConfiguration(
+                initialState = NumNode(1),
+                searchQueue = QueueBasedSearchQueue(),
+                expandNode = { node -> listOf(1, 2, 3, 4, 5).map { NumNode(it + node.num) } },
+                nodeFilter = { node -> true },
+                isFinalState = { node -> node.num == 42 }
+        )
+        val result = search(configuration, { msg -> println(msg) })
+        println("Found result $result")
+    }
+}