maven not compiling test code / not running test code - maven

Question

I have a simple Mavenized Java Project with the expected directory structure an no "business" classes yet:
The pom.xml is rather mundane. It declares dependencies on JUnit4 and JUnit5, and the "surefire" plugin (enclosing project noise elided):
<properties>
<junit5Version>5.1.0</junit5Version>
<junit4Version>4.12</junit4Version>
<commonsCodecVersion>20041127.091804</commonsCodecVersion>
<mavenCompilerPluginVersion>3.7.0</mavenCompilerPluginVersion>
<junitPlatformSurefireProviderVersion>1.1.0</junitPlatformSurefireProviderVersion>
<mavenSurefirePluginVersion>2.21.0</mavenSurefirePluginVersion>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<sourceDirectory>src</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>${mavenCompilerPluginVersion}</version>
<configuration>
<release>9</release>
</configuration>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>${mavenSurefirePluginVersion}</version>
<dependencies>
<dependency>
<groupId>org.junit.platform</groupId>
<artifactId>junit-platform-surefire-provider</artifactId>
<version>${junitPlatformSurefireProviderVersion}</version>
</dependency>
<dependency>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
<version>${junit5Version}</version>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>${junit5Version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
<!-- https://www.petrikainulainen.net/programming/testing/junit-5-tutorial-running-unit-tests-with-maven/ -->
<dependencies>
<!-- https://mvnrepository.com/artifact/commons-codec/commons-codec/ -->
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>${commonsCodecVersion}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit4Version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api -->
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>${junit5Version}</version>
</dependency>
</dependencies>
Problem:
In the above I don't not scope the junit:junit and
org.junit.jupiter.junit-jupiter-api dependencies to the test
scope. Indeed, if I do that, mvn compile fails because it cannot
find the symbols for JUnit4 and JUnit5. This is unexpected, I would
expect it to not actually compile the test code at all. Indeed
examples generally show restriction to the test scope. What's
wrong?
If there is no restriction to the test scope, then mvn compile works, but mvn test doesn't run any tests. The surefire plugin seems to not sniff out any JUnit tests, neither 4's nor 5's. What's wrong here?
And finally, version info:
$ mvn -version
Apache Maven 3.5.2
Maven home: /usr/local/java/maven
Java version: 9.0.4, vendor: Oracle Corporation

Answer 1

maven-surefire-plugin 2.21.0 is not compatible with version 1.1.0 of the junit-platform-surefire-provider.
Either rollback maven-surefire-plugin to 2.19.1 or update junit-platform-surefire-provider to 1.2.0-SNAPSHOT (or the 1.2.0 release if it's out).
The pom.xml to use if using the SNAPSHOT, with the Sonatype plugin repository configured:
<?xml version="1.0"?>
<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>
<groupId>TestJava</groupId>
<artifactId>TestJava</artifactId>
<version>0.0.1-SNAPSHOT</version>
<pluginRepositories>
<pluginRepository>
<id>oss-sonatype</id>
<name>oss-sonatype</name>
<url>https://oss.sonatype.org/content/repositories/snapshots/</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
<properties>
<junit5Version>5.1.0</junit5Version>
<junit4Version>4.12</junit4Version>
<mavenCompilerPluginVersion>3.7.0</mavenCompilerPluginVersion>
<junitPlatformSurefireProviderVersion>1.2.0-SNAPSHOT</junitPlatformSurefireProviderVersion>
<mavenSurefirePluginVersion>2.21.0</mavenSurefirePluginVersion>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>${mavenCompilerPluginVersion}</version>
<configuration>
<release>9</release>
</configuration>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>${mavenSurefirePluginVersion}</version>
<!-- https://www.petrikainulainen.net/programming/testing/junit-5-tutorial-running-unit-tests-with-maven/ -->
<dependencies>
<dependency>
<groupId>org.junit.platform</groupId>
<artifactId>junit-platform-surefire-provider</artifactId>
<version>${junitPlatformSurefireProviderVersion}</version>
</dependency>
<dependency>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
<version>${junit5Version}</version>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>${junit5Version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
<dependencies>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit4Version}</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api -->
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>${junit5Version}</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
Run mvn -U test to force a check for missing releases and updated snapshots on remote repositories.