added mvn and cicd

.github/workflows/ci.yml

@@ -0,0 +1,33 @@
+name: CI
+
+on:
+  push:
+    branches: [ "**" ]
+  pull_request:
+    branches: [ "**" ]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+          cache: maven
+
+      - name: Build and test
+        run: mvn --batch-mode verify
+
+      - name: Upload test report
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-report
+          path: target/surefire-reports/
+

.gitignore

@@ -2,4 +2,7 @@ out/
 .idea/
 build/
 .kotlin/
-*.class
+*.class
+
+# Maven
+target/

pom.xml

@@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
+                             https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.rubenjpdev</groupId>
+    <artifactId>order-matching-engine</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+
+    <properties>
+        <kotlin.version>2.1.20</kotlin.version>
+        <junit.version>5.10.2</junit.version>
+        <java.version>21</java.version>
+        <maven.compiler.source>${java.version}</maven.compiler.source>
+        <maven.compiler.target>${java.version}</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <dependencies>
+        <!-- Kotlin standard library -->
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib</artifactId>
+            <version>${kotlin.version}</version>
+        </dependency>
+
+        <!-- JUnit Jupiter (tests) -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <!-- Source directories -->
+        <sourceDirectory>src/main/java</sourceDirectory>
+        <testSourceDirectory>src/test/java</testSourceDirectory>
+
+        <plugins>
+            <!-- Kotlin compiler -->
+            <plugin>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <artifactId>kotlin-maven-plugin</artifactId>
+                <version>${kotlin.version}</version>
+                <executions>
+                    <execution>
+                        <id>compile</id>
+                        <goals><goal>compile</goal></goals>
+                        <configuration>
+                            <sourceDirs>
+                                <sourceDir>src/main/java</sourceDir>
+                            </sourceDirs>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>test-compile</id>
+                        <goals><goal>test-compile</goal></goals>
+                        <configuration>
+                            <sourceDirs>
+                                <sourceDir>src/test/java</sourceDir>
+                            </sourceDirs>
+                        </configuration>
+                    </execution>
+                </executions>
+                <configuration>
+                    <jvmTarget>${java.version}</jvmTarget>
+                </configuration>
+            </plugin>
+
+            <!-- Surefire: run JUnit 5 tests -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.2.5</version>
+            </plugin>
+        </plugins>
+    </build>
+</project>

src/test/java/com/rubenjpdev/ordermatching/engine/OrderBookTest.kt

@@ -247,7 +247,7 @@ class OrderBookTest {
 
             assertNull(book.asks[101L], "Level 101 must be pruned")
             assertNotNull(book.asks[102L], "Level 102 must still exist")
-            assertEquals(101L, book.asks.size.toLong().also { assertEquals(1L, it) }.let { 102L })
+            assertEquals(1, book.asks.size, "Only level 102 must remain")
         }
 
         @Test