From b459660385c0a3678df6d7c41400347b84bbd7b1 Mon Sep 17 00:00:00 2001
From: Szczepan Faber <sfaber@linkedin.com>
Date: Fri, 12 Aug 2016 19:15:03 -0700
Subject: [PATCH] Protected from null argument

Following neat feedback from Christian.

Issue #384
---
 .../framework/DefaultMockitoFramework.java    |  8 ++++++++
 .../DefaultMockitoFrameworkTest.java          | 19 +++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 src/test/java/org/mockito/internal/framework/DefaultMockitoFrameworkTest.java

diff --git a/src/main/java/org/mockito/internal/framework/DefaultMockitoFramework.java b/src/main/java/org/mockito/internal/framework/DefaultMockitoFramework.java
index 02df1e5f01..007a7c0ee7 100644
--- a/src/main/java/org/mockito/internal/framework/DefaultMockitoFramework.java
+++ b/src/main/java/org/mockito/internal/framework/DefaultMockitoFramework.java
@@ -21,12 +21,20 @@ public void setStubbingListener(StubbingListener listener) {
     }
 
     public void addListener(MockitoListener listener) {
+        assertNotNull(listener);
         if (listener instanceof MockCreationListener) {
             mockingProgress().addListener(listener);
         }
     }
 
     public void removeListener(MockitoListener listener) {
+        assertNotNull(listener);
         mockingProgress().removeListener(listener);
     }
+
+    private void assertNotNull(MockitoListener listener) {
+        if (listener == null) {
+            throw new IllegalArgumentException("listener cannot be null");
+        }
+    }
 }
\ No newline at end of file
diff --git a/src/test/java/org/mockito/internal/framework/DefaultMockitoFrameworkTest.java b/src/test/java/org/mockito/internal/framework/DefaultMockitoFrameworkTest.java
new file mode 100644
index 0000000000..02e9be9c01
--- /dev/null
+++ b/src/test/java/org/mockito/internal/framework/DefaultMockitoFrameworkTest.java
@@ -0,0 +1,19 @@
+package org.mockito.internal.framework;
+
+import org.junit.Test;
+import org.mockitoutil.TestBase;
+
+public class DefaultMockitoFrameworkTest extends TestBase {
+
+    DefaultMockitoFramework framework = new DefaultMockitoFramework();
+
+    @Test(expected = IllegalArgumentException.class)
+    public void prevents_adding_null_listener() {
+        framework.addListener(null);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void prevents_removing_null_listener() {
+        framework.addListener(null);
+    }
+}
\ No newline at end of file