Skip tests:

  mvn package -DskipTests

Fat JAR:

        <plugin>

            <groupId>org.apache.maven.plugins</groupId>

            <artifactId>maven-assembly-plugin</artifactId>

            <version>3.3.0</version>

            <configuration>

                <descriptorRefs>

                    <descriptorRef>jar-with-dependencies</descriptorRef>

                </descriptorRefs>

            </configuration>

            <executions>

                <execution>

                    <id>assemble-all</id>

                    <phase>package</phase>

                    <goals>

                        <goal>single</goal>

                    </goals>

                </execution>

            </executions>

        </plugin>

    </plugins>

  </build>

Then: mvn package