| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.codehaus.groovy.runtime |
| |
| import groovy.test.GroovyTestCase |
| |
| /** |
| * Test the customization of the Groovy truth, aka. boolean coercion. |
| * It is possible to customize how instances of a type are coerced into boolean |
| * by implementing a method with the following signature: |
| * <code>boolean asBoolean()</code> |
| * <p> |
| * The test also checks it's possible to override the behaviour of pre-existing boolean coercion. |
| */ |
| class CustomBooleanCoercionTest extends GroovyTestCase { |
| |
| void testPredefinedGroovyTruth() { |
| // null is false |
| def nullVar = null |
| assert !nullVar |
| |
| // non-null object is true |
| def obj = new Object() |
| assert obj |
| |
| // empty strings are false, and >1 length strings are true |
| assert !"" |
| assert " \t \n " |
| assert "Groovy Truth" |
| |
| // characters are true unless if it's the zeroth one |
| char c0 = '\0' |
| char c1 = 'a' |
| assert !c0 |
| assert c1 |
| |
| // empty lists are true, and list with 1+ elements are true |
| assert ![] |
| assert [1, 2, 3] |
| assert 1..10 |
| |
| // empty maps are false, and non-empty maps are true |
| assert ![:] |
| assert [firstname: 'Guillaume', lastname: 'Laforge'] |
| |
| // number equal to 0 is false, and true otherwise |
| assert !0 |
| assert 1 |
| assert !0.0 |
| assert 1.1 |
| |
| // an iterator is true if there are other elements to iterate over, false otherwise |
| assert ![].iterator() |
| assert [1, 2, 3].iterator() |
| |
| assert Boolean.TRUE |
| assert !Boolean.FALSE |
| |
| // empty arrays are false, non-empty are true |
| assert !([] as Object[]) |
| assert [1, 2, 3] as int[] |
| } |
| |
| /** |
| * A Predicate instance should coerce to the same boolean as the one in the value property of the instance |
| */ |
| void testCustomAsBooleanMethod() { |
| assert new Predicate(value: true) |
| assert !new Predicate(value: false) |
| } |
| |
| void testOverrideAsBooleanMethodWithACategory() { |
| use (BoolCategory) { |
| assert !new Predicate(value: true) |
| assert new Predicate(value: false) |
| } |
| } |
| |
| void testOverrideAsBooleanMethodWithEMC() { |
| try { |
| Predicate.metaClass.asBoolean = { -> true } |
| assert new Predicate(value: true) |
| assert new Predicate(value: false) |
| } finally { |
| Predicate.metaClass = null |
| } |
| } |
| |
| void testOverrideStringAsBooleanThroughEMC() { |
| try { |
| String.metaClass.asBoolean = { -> true } |
| |
| assert "" |
| assert " \t \n " |
| assert "ok" |
| assert "true" |
| assert "false" |
| assert "Groovy rocks!" |
| } finally { |
| String.metaClass = null |
| } |
| } |
| } |
| |
| /** A Predicate class coercible to a boolean expression */ |
| class Predicate { |
| boolean value |
| boolean asBoolean() { value } |
| } |
| |
| /** A Boolean Category which coerces the boolean value to its opposite */ |
| class BoolCategory { |
| static boolean asBoolean(Predicate self) { |
| !self.value |
| } |
| } |