Merge pull request #259 from qbicsoftware/hotfix/2.12.1

Sync of hotfix 2.12.1

Author: jenniferboedker

CHANGELOG.rst

@@ -15,6 +15,18 @@ This project adheres to `Semantic Versioning <https://semver.org/>`_.
 
 **Deprecated**
 
+2.12.1 (2021-09-13)
+-------------------
+
+**Added**
+
+**Fixed**
+
+* NPE when comparing ``life.qbic.datamodel.dtos.projectmanagement.ProjectIdentifier`` to null reference (`#258 <https://github.com/qbicsoftware/data-model-lib/pull/258>`_)
+
+**Dependencies**
+
+**Deprecated**
 
 2.12.0 (2021-09-10)
 -------------------

src/main/groovy/life/qbic/datamodel/dtos/projectmanagement/ProjectIdentifier.groovy

@@ -36,6 +36,9 @@ class ProjectIdentifier {
 
     @Override
     boolean equals(Object obj) {
+        if (obj == null) {
+            return false
+        }
         if (this.is(obj)) {
             return true
         }

src/test/groovy/life/qbic/datamodel/dtos/projectmanagement/ProjectIdentifierSpec.groovy

@@ -40,4 +40,26 @@ class ProjectIdentifierSpec extends Specification{
 
     }
 
+    /**
+     * Tests for Joshua Bloch's Item 8 in Effective Java, how to override equals() properly.
+     * https://biratkirat.medium.com/learning-effective-java-item-8-d05f3847213d
+     */
+    def "Test equals method fulfills full method contract"() {
+        when:
+        ProjectIdentifier idX = new ProjectIdentifier(new ProjectSpace(projectSpace), new ProjectCode(projectCode))
+        ProjectIdentifier idY = new ProjectIdentifier(new ProjectSpace(projectSpace), new ProjectCode(projectCode))
+        ProjectIdentifier idZ = new ProjectIdentifier(new ProjectSpace(projectSpace), new ProjectCode(projectCode))
+
+        then:
+        idX.equals(idX) == true // Reflexive
+        (idX.equals(idY) == true) && (idY.equals(idX) == true) // Symmetric
+        (idX.equals(idY) == true) && (idY.equals(idZ) == true) && (idX.equals(idZ) == true) // Transitive
+        (idX.equals(idX) == true) && (idX.equals(idX) == true) // Consistent
+        idX.equals(null) == false // Non-nullity
+
+        where:
+        projectSpace | projectCode
+        "TEST" | "QTEST"
+    }
+
 }