[JENKINS-15094] - Unit tests for the issue

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

core/src/test/java/hudson/model/ParametersActionTest.java

@@ -1,11 +1,21 @@
 package hudson.model;
 
+import hudson.EnvVars;
+import hudson.model.queue.SubTask;
+import hudson.tasks.BuildWrapper;
+import java.util.LinkedList;
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotSame;
+import org.junit.runner.RunWith;
+import org.jvnet.hudson.test.Bug;
+import static org.powermock.api.mockito.PowerMockito.mock;
+import org.powermock.modules.junit4.PowerMockRunner;
 
+@RunWith(PowerMockRunner.class)
 public class ParametersActionTest {
 
     private ParametersAction baseParamsAB;
@@ -76,4 +86,35 @@ public class ParametersActionTest {
 
         assertNotSame(baseParamsAB, params);
     }
+    
+    @Test
+    @Bug(15094)   
+    public void checkNullParamaterValues() {
+        SubTask subtask = mock(SubTask.class);
+        Build build = mock(Build.class);
+                   
+        // Prepare parameters Action
+        StringParameterValue A = new StringParameterValue("A", "foo");
+        StringParameterValue B = new StringParameterValue("B", "bar");
+        ParametersAction parametersAction = new ParametersAction(A, null, B);
+        ParametersAction parametersAction2 = new ParametersAction(A,null);
+        
+        // Non existent parameter
+        assertNull(parametersAction.getParameter("C"));   
+        assertNull(parametersAction.getAssignedLabel(subtask));
+        
+        // Interaction with build
+        EnvVars vars = new EnvVars();
+        parametersAction.buildEnvVars(build, vars);
+        assertEquals(2, vars.size());   
+        parametersAction.createVariableResolver(build);
+        
+        LinkedList<BuildWrapper> wrappers = new LinkedList<BuildWrapper>();
+        parametersAction.createBuildWrappers(build, wrappers);
+        assertEquals(0, wrappers.size());
+        
+        // Merges and overrides
+        assertEquals(3, parametersAction.createUpdated(parametersAction2.getParameters()).getParameters().size());
+        assertEquals(3, parametersAction.merge(parametersAction2).getParameters().size());        
+    }
 }