diff --git a/node.iml b/node.iml
index a66a2bf..b2d3a3d 100644
--- a/node.iml
+++ b/node.iml
@@ -14,5 +14,6 @@
     <orderEntry type="library" scope="TEST" name="Maven: org.projectlombok:lombok:1.16.8" level="project" />
     <orderEntry type="library" scope="TEST" name="Maven: junit:junit:4.12" level="project" />
     <orderEntry type="library" scope="TEST" name="Maven: org.hamcrest:hamcrest-core:1.3" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.assertj:assertj-core:3.4.1" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index 32577de..c488538 100644
--- a/pom.xml
+++ b/pom.xml
@@ -14,6 +14,10 @@
         <version>0.6.0</version>
     </parent>
 
+    <properties>
+        <assertj.version>3.4.1</assertj.version>
+    </properties>
+
     <issueManagement>
         <url>https://github.com/kemitix/node/issues</url>
         <system>GitHub Issues</system>
@@ -48,5 +52,11 @@
             <version>1.3</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>