未在maven中执行testNG文件

我在maven项目中有一个testNG脚本，但当我执行mvn测试时，该脚本不会执行

pom.xml文件

<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>xgen</groupId>
  <artifactId>smart_collect</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>smart_collect</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

    <dependencies>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-java</artifactId>
            <version>3.5.3</version>
        </dependency>
        <dependency>
            <groupId>org.testng</groupId>
            <artifactId>testng</artifactId>
            <version>6.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

我的文件夹结构

我的maven输出

---

我需要知道为什么会这样。当我用testNG运行它时，它工作得很好，POM不知道要运行哪个文件。按照以下步骤使其工作

创建一个testng.xml文件，并在pom.xml之前添加以下代码，然后尝试运行

 <build>
        <!-- Source directory configuration -->
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <!-- Following plugin executes the testng tests -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.14.1</version>
                <configuration>
                    <!-- Suite testng xml file to consider for test execution -->
                    <suiteXmlFiles>
                        <suiteXmlFile>testng.xml</suiteXmlFile>
                        <suiteXmlFile>suites-test-testng.xml</suiteXmlFile>
                    </suiteXmlFiles>
                </configuration>
            </plugin>
            <!-- Compiler plugin configures the java version to be usedfor compiling
                the code -->
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

 <build>
        <!-- Source directory configuration -->
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <!-- Following plugin executes the testng tests -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.14.1</version>
                <configuration>
                    <!-- Suite testng xml file to consider for test execution -->
                    <suiteXmlFiles>
                        <suiteXmlFile>testng.xml</suiteXmlFile>
                        <suiteXmlFile>suites-test-testng.xml</suiteXmlFile>
                    </suiteXmlFiles>
                </configuration>
            </plugin>
            <!-- Compiler plugin configures the java version to be usedfor compiling
                the code -->
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
        </plugins>
    </build>