Maven skip tests

Question

I have been using Maven 2.2.1 and to build my project I used this command

mvn clean install -Dmaven.test.skip=true

However, the build failed saying it couldn't find one of the artifacts. However, when I used:

mvn clean install -DskipTests

Everything worked fine and since then, I have been thinking that these 2 commands are equivalent. However, the link seems to suggest that -Dmaven.test.skip=true also skips compiling the test cases. However, that still didn't explain to me why one command is working and another is not. It will be great if anyone please explain this to me.

Answer 1

You have correctly pointed out that the -Dmaven.test.skip=true will skip compiling the tests. This will also skip building the test artifacts like you mentioned. However, a common practice for large projects is to have testing utilities and various base classes shared among modules in the same project. The code below is accomplished by having a module require a test-jar of a previously built module:
 

<dependency> 
    <groupId>org.myproject.mygroup</groupId>
  <artifactId>common</artifactId> 
  <version>1.0</version> 
  <type>test-jar</type>
  <scope>test</scope> 
</dependency>

If the -Dmaven.test.skip=true has been elaborately stated, then test-jars aren't built, and any module that relies on them will fail to build obviously. Following that, once you use -DskipTests, Maven does not run the tests, but it does compile them and build the test-jar, making it available for the subsequent modules.