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1   /*
2    * Copyright 2003,2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.apache.commons.jexl.junit;
18  
19  import java.util.HashMap;
20  import java.util.Map;
21  
22  import junit.framework.Assert;
23  
24  import org.apache.commons.jexl.Expression;
25  import org.apache.commons.jexl.ExpressionFactory;
26  import org.apache.commons.jexl.JexlContext;
27  import org.apache.commons.jexl.JexlHelper;
28  
29  /***
30   * A utility class for performing JUnit based assertions using Jexl
31   * expressions. This class can make it easier to do unit tests using
32   * Jexl navigation expressions.
33   *
34   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
35   * @version $Revision: 1.4 $
36   */
37  public class Asserter extends Assert {
38  
39      private Map variables = new HashMap();
40      private JexlContext context = JexlHelper.createContext();
41  
42      public Asserter() {}
43  
44      /***
45       * This constructor will register the given variableValue as the
46       * "this" variable.
47       * 
48       * @param variableValue
49       */
50      public Asserter(Object variableValue) {
51          setVariable("this", variableValue);
52      }
53  
54      /***
55       * Performs an assertion that the value of the given Jexl expression 
56       * evaluates to the given expected value
57       * 
58       * @param expression is the Jexl expression to evaluate
59       * @param expected is the expected value of the expression
60       * @throws Exception if the expression could not be evaluationed or an assertion
61       * fails
62       */
63      public void assertExpression(String expression, Object expected) throws Exception {
64          Expression exp = ExpressionFactory.createExpression(expression);
65  
66          context.setVars(variables);
67          Object value = exp.evaluate(context);
68  
69          assertEquals("expression: " + expression, expected, value);
70      }
71  
72      /***
73       * Puts a variable of a certain name in the context so that it can be used from
74       * assertion expressions.
75       * 
76       * @param name
77       * @param value
78       */
79      public void setVariable(String name, Object value) {
80          variables.put(name, value);
81      }
82  
83  }