Extended test.

hooks/test/test_test.go

diff --git a/hooks/test/test_test.go b/hooks/test/test_test.go
index fabe46f..d69455b 100644
--- a/hooks/test/test_test.go
+++ b/hooks/test/test_test.go
@@ -12,6 +12,8 @@
 	assert := assert.New(t)
 
 	logger, hook := NewNullLogger()
+	assert.Nil(hook.LastEntry())
+	assert.Equal(0, len(hook.Entries))
 
 	logger.Error("Hello error")
 	assert.Equal(logrus.ErrorLevel, hook.LastEntry().Level)
@@ -24,6 +26,7 @@
 	assert.Equal(2, len(hook.Entries))
 
 	hook.Reset()
+	assert.Nil(hook.LastEntry())
 	assert.Equal(0, len(hook.Entries))
 
 	hook = NewGlobal()