BAEL-2911 - JUnit Custom Display Name Generator API

testing-modules/junit-5-advanced/pom.xml

@@ -0,0 +1,32 @@
+<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>junit-5-advanced</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>junit-5-advanced</name>
+    <description>Advanced JUnit 5 Topics</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit-jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    
+    <properties>
+        <junit-jupiter.version>5.4.2</junit-jupiter.version>
+        <maven-surefire-plugin.version>2.21.0</maven-surefire-plugin.version>
+    </properties>
+
+</project>

testing-modules/junit-5-advanced/src/test/java/com/baeldung/displayname/DisplayNameGeneratorUnitTest.java

@@ -0,0 +1,87 @@
+package com.baeldung.displayname;
+
+import org.junit.jupiter.api.DisplayNameGeneration;
+import org.junit.jupiter.api.DisplayNameGenerator;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import java.lang.reflect.Method;
+
+@DisplayNameGeneration(DisplayNameGeneratorUnitTest.ReplaceCamelCase.class)
+class DisplayNameGeneratorUnitTest {
+
+    @Test
+    void camelCaseName() {
+    }
+
+    @Nested
+    @DisplayNameGeneration(DisplayNameGeneratorUnitTest.IndicativeSentences.class)
+    class ANumberIsFizz {
+        @Test
+        void ifItIsDivisibleByThree() {
+        }
+
+        @ParameterizedTest(name = "Number {0} is fizz.")
+        @ValueSource(ints = { 3, 12, 18 })
+        void ifItIsOneOfTheFollowingNumbers(int number) {
+        }
+    }
+
+    @Nested
+    @DisplayNameGeneration(DisplayNameGeneratorUnitTest.IndicativeSentences.class)
+    class ANumberIsBuzz {
+        @Test
+        void ifItIsDivisibleByFive() {
+        }
+
+        @ParameterizedTest(name = "Number {0} is buzz.")
+        @ValueSource(ints = { 5, 10, 20 })
+        void ifItIsOneOfTheFollowingNumbers(int number) {
+        }
+    }
+
+    static class IndicativeSentences extends ReplaceCamelCase {
+        @Override
+        public String generateDisplayNameForNestedClass(Class<?> nestedClass) {
+            return super.generateDisplayNameForNestedClass(nestedClass) + "...";
+        }
+
+        @Override
+        public String generateDisplayNameForMethod(Class<?> testClass, Method testMethod) {
+            return replaceCamelCase(testClass.getSimpleName() + " " + testMethod.getName()) + ".";
+        }
+    }
+
+    static class ReplaceCamelCase extends DisplayNameGenerator.Standard {
+        @Override
+        public String generateDisplayNameForClass(Class<?> testClass) {
+            return replaceCamelCase(super.generateDisplayNameForClass(testClass));
+        }
+
+        @Override
+        public String generateDisplayNameForNestedClass(Class<?> nestedClass) {
+            return replaceCamelCase(super.generateDisplayNameForNestedClass(nestedClass));
+        }
+
+        @Override
+        public String generateDisplayNameForMethod(Class<?> testClass, Method testMethod) {
+            return this.replaceCamelCase(testMethod.getName()) + DisplayNameGenerator.parameterTypesAsString(testMethod);
+        }
+
+        String replaceCamelCase(String camelCase) {
+            StringBuilder result = new StringBuilder();
+            result.append(camelCase.charAt(0));
+            for (int i=1; i<camelCase.length(); i++) {
+                if (Character.isUpperCase(camelCase.charAt(i))) {
+                    result.append(' ');
+                    result.append(Character.toLowerCase(camelCase.charAt(i)));
+                } else {
+                    result.append(camelCase.charAt(i));
+                }
+            }
+            return result.toString();
+        }
+    }
+}

testing-modules/pom.xml

@@ -33,5 +33,6 @@
         <module>testing</module>
         <module>testng</module>
         <module>junit-5-basics</module>
+        <module>junit-5-advanced</module>
     </modules>
 </project>