variablereferencetest.java

不管是测试驱动开发或者是其它的开发模式

/*  Copyright (c) 2000-2004 jMock.org
 */
package test.jmock.examples.calculator.expression;

import org.jmock.Mock;
import org.jmock.MockObjectTestCase;
import org.jmock.examples.calculator.CalculatorException;
import org.jmock.examples.calculator.Environment;
import org.jmock.examples.calculator.Expression;
import org.jmock.examples.calculator.SimpleEnvironment;
import org.jmock.examples.calculator.expression.VariableReference;


public class VariableReferenceTest extends MockObjectTestCase
{

    private final String variableName = "VARIABLE NAME";
    private Mock mockDefinition;
    private VariableReference variableReference;

    public void setUp() {
        mockDefinition = mock(Expression.class, "mockDefinition");
        variableReference = new VariableReference(variableName);
    }

    public void testEvaluatesDefinitionOfReferencedVariable() throws Exception {
        Mock mockEnvironment = mock(Environment.class);
        double result = 1234;

        mockEnvironment.expects(once()).method("getVariable").with(eq(variableName))
                .will(returnValue(mockDefinition.proxy()));
        mockDefinition.expects(once()).method("evaluate").with(same(mockEnvironment.proxy()))
                .will(returnValue(result));

        assertEquals("should be result of evaluating variable definition",
                     result,
                     variableReference.evaluate((Environment)mockEnvironment.proxy()),
                     0);
    }

    public void testPassesBackExceptionsFromVariableDefiniton() {
        SimpleEnvironment environment = new SimpleEnvironment();
        environment.setVariable(variableName, (Expression)mockDefinition.proxy());
        CalculatorException thrown = new CalculatorException("THROWN EXCEPTION");

        mockDefinition.expects(once()).method("evaluate").with(eq(environment))
                .will(throwException(thrown));

        try {
            variableReference.evaluate(environment);
            fail("expected CalculatorException to be thrown");
        }
        catch (CalculatorException caught) {
            assertSame("should be thrown exception", thrown, caught);
        }
    }

    public void testThrowsCalculatorExceptionIfVariableNotDefined() {
        SimpleEnvironment environment = new SimpleEnvironment();

        try {
            variableReference.evaluate(environment);
            fail("expected CalculatorException to be thrown");
        }
        catch (CalculatorException ex) {
            assertTrue("should contain variable name in message",
                       ex.getMessage().indexOf(variableName) >= 0);
        }
    }
}