more testing

Author: cowtowncoder

src/main/java/com/fasterxml/jackson/databind/DatabindContext.java

@@ -134,7 +134,10 @@ public abstract class DatabindContext
      * type (usually {@link java.lang.Class})
      */
     public JavaType constructType(Type type) {
-         return getTypeFactory().constructType(type);
+        if (type == null) {
+            return null;
+        }
+        return getTypeFactory().constructType(type);
     }
 
     /**

src/test/java/com/fasterxml/jackson/databind/cfg/DatabindContextTest.java

@@ -0,0 +1,22 @@
+package com.fasterxml.jackson.databind.cfg;
+
+import com.fasterxml.jackson.databind.*;
+
+public class DatabindContextTest extends BaseMapTest
+{
+    private final ObjectMapper MAPPER = objectMapper();
+
+    public void testDeserializationContext() throws Exception
+    {
+        DeserializationContext ctxt = MAPPER.getDeserializationContext();
+        // should be ok to try to resolve `null`
+        assertNull(ctxt.constructType((Class<?>) null));
+        assertNull(ctxt.constructType((java.lang.reflect.Type) null));
+    }
+
+    public void testSerializationContext() throws Exception
+    {
+        SerializerProvider ctxt = MAPPER.getSerializerProvider();
+        assertNull(ctxt.constructType(null));
+    }
+}