diff --git a/gclc/src/main/java/fr/bigeon/gclc/ApplicationAttachement.java b/gclc/src/main/java/fr/bigeon/gclc/ApplicationAttachement.java
index 5a3cc38..e64ccd6 100644
--- a/gclc/src/main/java/fr/bigeon/gclc/ApplicationAttachement.java
+++ b/gclc/src/main/java/fr/bigeon/gclc/ApplicationAttachement.java
@@ -40,13 +40,9 @@ package fr.bigeon.gclc;
 
 import fr.bigeon.gclc.exception.InvalidCommandName;
 
-/**
- * <p>
- * TODO
+/** Represent a functionnality set that can be added to a console application.
  *
- * @author Emmanuel Bigeon
- *
- */
+ * @author Emmanuel Bigeon */
 public interface ApplicationAttachement {
     /** Attach this object to a console application.
      * <p>
diff --git a/gclc/src/main/java/fr/bigeon/gclc/proc/TaskPool.java b/gclc/src/main/java/fr/bigeon/gclc/proc/TaskPool.java
index cd14e83..dfe2865 100644
--- a/gclc/src/main/java/fr/bigeon/gclc/proc/TaskPool.java
+++ b/gclc/src/main/java/fr/bigeon/gclc/proc/TaskPool.java
@@ -56,8 +56,12 @@ public class TaskPool {
 
     /** Add a process in the pool
      * 
-     * @param cmd the process */
-    public void add(final Task cmd) {
+     * @param cmd the process
+     * @return the pid */
+    public String add(final Task cmd) {
+        if (cmd == null) {
+            throw new NullPointerException("Task cannot be null"); //$NON-NLS-1$
+        }
         final String pid = getPID();
         synchronized (lock) {
             running.put(pid, cmd);
@@ -74,6 +78,7 @@ public class TaskPool {
                 cmd.rmInterruptionListener(this);
             }
         });
+        return pid;
     }
 
     /** @return the process id */
diff --git a/gclc/src/test/java/fr/bigeon/gclc/proc/ProcessListTest.java b/gclc/src/test/java/fr/bigeon/gclc/proc/ProcessListTest.java
new file mode 100644
index 0000000..6d8b401
--- /dev/null
+++ b/gclc/src/test/java/fr/bigeon/gclc/proc/ProcessListTest.java
@@ -0,0 +1,82 @@
+/**
+ * gclc:fr.bigeon.gclc.proc.ProcessListTest.java
+ * Created on: Aug 19, 2017
+ */
+package fr.bigeon.gclc.proc;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import fr.bigeon.gclc.exception.CommandRunException;
+import fr.bigeon.gclc.manager.PipedConsoleManager;
+
+/**
+ * <p>
+ * TODO
+ *
+ * @author Emmanuel Bigeon
+ *
+ */
+public class ProcessListTest {
+
+    /** Test method for
+     * {@link fr.bigeon.gclc.proc.ProcessList#execute(java.lang.String[])}.
+     * 
+     * @throws CommandRunException if an error occured in the execution
+     * @throws IOException if the manager could not be created */
+    @Test
+    public final void testExecute() throws CommandRunException, IOException {
+        TaskPool pool = new TaskPool();
+        ProcessList pl = new ProcessList("list", pool,
+                new PipedConsoleManager());
+            pl.execute();
+        pool.add(new Task() {
+
+            @Override
+            public void run() {
+                // TODO Auto-generated method stub
+                //
+                throw new RuntimeException("Not implemented yet");
+            }
+
+            @Override
+            public void setRunning(boolean running) {
+                //
+            }
+
+            @Override
+            public void rmInterruptionListener(InterruptionListener listener) {
+                //
+            }
+
+            @Override
+            public boolean isRunning() {
+                return false;
+            }
+
+            @Override
+            public String getName() {
+                return "name";
+            }
+
+            @Override
+            public void addInterruptionListener(InterruptionListener listener) {
+                //
+            }
+        });
+        pl.execute();
+    }
+
+    @Test
+    public void testTip() {
+        try {
+            new ProcessList("list", new TaskPool(), new PipedConsoleManager())
+                    .tip();
+        } catch (IOException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
+
+    }
+}
diff --git a/gclc/src/test/java/fr/bigeon/gclc/proc/TaskPoolTest.java b/gclc/src/test/java/fr/bigeon/gclc/proc/TaskPoolTest.java
new file mode 100644
index 0000000..0533230
--- /dev/null
+++ b/gclc/src/test/java/fr/bigeon/gclc/proc/TaskPoolTest.java
@@ -0,0 +1,98 @@
+/**
+ * gclc:fr.bigeon.gclc.proc.TaskPoolTest.java
+ * Created on: Aug 19, 2017
+ */
+package fr.bigeon.gclc.proc;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.fail;
+
+import org.junit.Test;
+
+/**
+ * <p>
+ * TODO
+ *
+ * @author Emmanuel Bigeon */
+public class TaskPoolTest {
+
+    /** Test method for
+     * {@link fr.bigeon.gclc.proc.TaskPool#add(fr.bigeon.gclc.proc.Task)}. */
+    @Test
+    public final void testAdd() {
+        TaskPool pool = new TaskPool();
+        Task task = null;
+        try {
+            pool.add(task);
+            fail("Expected a null pointer exception");
+        } catch (NullPointerException e) {
+            assertNotNull(e);
+        }
+        task = new Task() {
+            private final Object lock = new Object();
+            private boolean running;
+            private InterruptionListener listener;
+
+            @Override
+            public void run() {
+                synchronized (lock) {
+                    while (running) {
+                        try {
+                            lock.wait(100);
+                        } catch (InterruptedException e) {
+                            // TODO Auto-generated catch block
+                            e.printStackTrace();
+                        }
+                    }
+                }
+                listener.interrupted();
+            }
+
+            @Override
+            public void setRunning(boolean running) {
+                synchronized (lock) {
+                    this.running = running;
+                }
+                //
+            }
+
+            @Override
+            public void rmInterruptionListener(InterruptionListener listener) {
+                //
+            }
+
+            @Override
+            public boolean isRunning() {
+                return running;
+            }
+
+            @Override
+            public String getName() {
+                return "Test";
+            }
+
+            @Override
+            public void addInterruptionListener(InterruptionListener listener) {
+                this.listener = listener;
+            }
+        };
+        pool.add(task);
+        assertEquals(1, pool.getPIDs().size());
+
+        for (String pid : pool.getPIDs()) {
+            assertEquals(task, pool.get(pid));
+        }
+        Thread th = new Thread(task);
+        th.start();
+        task.setRunning(false);
+        try {
+            th.join(1000);
+        } catch (InterruptedException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
+
+        assertEquals(0, pool.getPIDs().size());
+    }
+}