title: How to set a flattened test/source folder structure?
body: <p>Using gradle for a Java+Groovy+JUnit project, I get this source folder structure by default:</p>
  
  <pre><code>prjroot-src
  ├── main
  │   ├── groovy
  │   └── java
  └── test
      ├── groovy
      └── java
  </code></pre>
  
  <p>I wanted to have Java and Groovy sources in one folder, so I set the <code>sourceSets</code> like this:</p>
  
  <pre><code>sourceSets.main.java.srcDirs = []
  sourceSets.main.groovy.srcDirs += ["src/main/java"]
  </code></pre>
  
  <p>Which resulted in the same directory structure with the difference that I could put my .groovy files in the java folder. Also, the unused Groovy folder still is there.</p>
  
  <p>I'd like a much flatter, cleaner directory structure that looks like this:</p>
  
  <pre><code>prjroot
  ├── src
  └── test 
  </code></pre>
  
  <p>The packages, .groovy and .java files should be directly under src, and the test sources accordingly under test.</p>
  
  <p>How can I achieve this using gradle?</p>