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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 * @since 1.0
35 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
36 * @version $Revision: 398153 $
37 */
38 public class Asserter extends Assert {
39
40 /*** variables used during asserts. */
41 private final Map variables = new HashMap();
42 /*** context to use during asserts. */
43 private final JexlContext context = JexlHelper.createContext();
44
45 /***
46 *
47 * Create an asserter.
48 */
49 public Asserter() {
50
51 }
52
53 /***
54 * This constructor will register the given variableValue as the
55 * "this" variable.
56 *
57 * @param variableValue 'this'.
58 */
59 public Asserter(Object variableValue) {
60 setVariable("this", variableValue);
61 }
62
63 /***
64 * Performs an assertion that the value of the given Jexl expression
65 * evaluates to the given expected value.
66 *
67 * @param expression is the Jexl expression to evaluate
68 * @param expected is the expected value of the expression
69 * @throws Exception if the expression could not be evaluationed or an assertion
70 * fails
71 */
72 public void assertExpression(String expression, Object expected) throws Exception {
73 Expression exp = ExpressionFactory.createExpression(expression);
74
75 context.setVars(variables);
76 Object value = exp.evaluate(context);
77
78 assertEquals("expression: " + expression, expected, value);
79 }
80
81 /***
82 * Puts a variable of a certain name in the context so that it can be used from
83 * assertion expressions.
84 *
85 * @param name variable name
86 * @param value variable value
87 */
88 public void setVariable(String name, Object value) {
89 variables.put(name, value);
90 }
91
92 }