Java tutorial
/* * Copyright (c) 2008 Kevin Brockhoff * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package org.codekaizen.vtj; import static org.testng.Assert.*; import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import org.apache.commons.lang.ObjectUtils; import org.apache.commons.lang.SerializationUtils; import org.codekaizen.vtj.enums.EnumValueType; import org.testng.annotations.Test; /** * <p>Base class for unit testing implementations of {@link ValueType}. It tests serialization and the following methods * all value types should implement.</p> * * <ul> * <li><code>copy()</code></li> * <li><code>compareTo(T o)</code></li> * <li><code>hashCode()</code></li> * <li><code>equals(Object obj)</code></li> * <li><code>toString()</code></li> * </ul> * * @author <a href="mailto:kbrockhoff@codekaizen.org">Kevin Brockhoff</a> */ public abstract class AbstractValueTypeTest { private final Class<?> testClass; private final Class<?>[] constructorArgClasses; private final Object[] constructorArgs; private final boolean enumType; private EnumValueType<?> defaultEnum; private Constructor<?> constructor; /** * Constructs a {@link ValueType} implementation unit test. * * @param testCls the concrete class being tested * @param cnstrtCls the class(es) of the arguments for the default constructor * @param cnstrtArgs the constructor arguments to use * * @throws IllegalArgumentException if an invalid parameter is passed in */ protected AbstractValueTypeTest(final Class<?> testCls, final Class<?>[] cnstrtCls, final Object[] cnstrtArgs) { super(); AssertPrecondition.notNull("testCls", testCls); AssertPrecondition.isAssignable(ValueType.class, testCls); AssertPrecondition.notNull("cnstrsCls", cnstrtCls); AssertPrecondition.notNull("cnstrsArgs", cnstrtArgs); if (cnstrtCls.length != cnstrtArgs.length) { throw new IllegalArgumentException( "the number of arguments " + "does not match the constructor param classes count"); } enumType = EnumValueType.class.isAssignableFrom(testCls); testClass = testCls; constructorArgClasses = cnstrtCls; constructorArgs = cnstrtArgs; validateConstruction(); } private void validateConstruction() throws IllegalStateException, SecurityException, IllegalArgumentException { if (enumType) { // assume it is a Java 5 enum try { final Method m = testClass.getMethod("values", (Class<?>[]) null); final Enum<?>[] vals = (Enum<?>[]) m.invoke((Object) null); defaultEnum = (EnumValueType<?>) vals[0]; } catch (final Exception e) { throw new IllegalStateException(e); } } else { try { constructor = getTestClass().getConstructor(constructorArgClasses); } catch (final NoSuchMethodException nsme) { throw new IllegalArgumentException("constructor parameter classes are not valid", nsme); } try { constructor.newInstance(constructorArgs); } catch (InvocationTargetException ite) { throw new IllegalArgumentException("constructor arguments are not valid", ite.getCause()); } catch (final Exception e) { throw new IllegalStateException("unable to construct test object", e); } } } /** * Returns the implementing class being tested. * * @return the class */ protected final Class<?> getTestClass() { return testClass; } /** * Returns an instance of the class being tested populated with the default values. * * @return the constructed object or <code>null</code> if problems which should not happen because it is checked in * the constructor */ protected final ValueType<?> getDefaultTestInstance() { if (enumType) { return defaultEnum; } else { try { return (ValueType<?>) constructor.newInstance(constructorArgs); } catch (final Exception e) { return null; } } } /** * Verifies the class has no setter methods. */ @Test(groups = { "api" }) public final void shouldBeImmutable() { final Method[] methods = getTestClass().getMethods(); for (final Method method : methods) { if (Modifier.isStatic(method.getModifiers())) { continue; } assertFalse(method.getName().startsWith("set")); } } /** * Verifies that comparison with the same instance returns equals=<code>true</code>. */ @Test(groups = { "api" }) public final void shouldBeEqualsForSameObject() { final ValueType<?> vt1 = getDefaultTestInstance(); assertTrue(vt1.equals(vt1)); assertEquals(vt1.hashCode(), vt1.hashCode()); } /** * Verifies that passing in a <code>null</code> to equals returns <code>false</code> and does not throw a <code> * NullPointerException</code>. */ @Test(groups = { "api" }) public final void shouldBeNotEqualsForNull() { final ValueType<?> vt1 = getDefaultTestInstance(); assertFalse(vt1.equals(null)); } /** * Verifies that equals compares on object contents instead of the default identity by passing in another instance * to equals with the same underlying value. */ @Test(groups = { "api" }) public final void shouldBeEqualsForEquivalentButDifferentObject() { final ValueType<?> vt1 = getDefaultTestInstance(); final ValueType<?> vt2 = getDefaultTestInstance(); if (!(vt1 instanceof Enum)) { assertFalse(vt1 == vt2); } assertTrue(vt1.equals(vt2)); assertEquals(vt1.hashCode(), vt2.hashCode()); } /** * Verifies that equals returns <code>false</code> for two instances of the class being tested that wrap different * content. */ @Test(groups = { "api" }) public final void shouldBeNotEqualsForNonEquivalentObjectsOfSameType() { doNonEqualsTesting(); } /** * Verifies that equals returns <code>false</code> if an instance of a different class is passed in and does not * throw a <code>ClassCastException</code>. */ @Test(groups = { "api" }) public final void shouldBeNotEqualsForDifferentType() { final ValueType<?> vt1 = getDefaultTestInstance(); assertFalse(vt1.equals("A non ValueType object")); assertFalse(vt1.equals(vt1.toString())); } /** * Verifies that <code>copy</code> returns a new instance. */ @Test(groups = { "api" }) public final void shouldReturnEquivalentCopyButNotSameObjectUnlessEnum() { final ValueType<?> vt1 = getDefaultTestInstance(); final ValueType<?> vt2 = (ValueType<?>) vt1.copy(); assertEquals(vt2, vt1); if (!enumType) { assertNotSame(vt1, vt2); } } /** * Verifies that class implements <code>Comparable</code> correctly. */ @Test(groups = { "api" }) public final void shouldImplementComparable() { final ValueType<?> vt1 = getDefaultTestInstance(); assertTrue(vt1 instanceof Comparable); doCompareToTesting(); } /** * Verifies that a <code>NullPointerException</code> is thrown if <code>null</code> is passed into <code> * compareTo</code>. */ @Test(expectedExceptions = NullPointerException.class, groups = { "api" }) public final void shouldThrowExceptionComparingNull() { final ValueType<?> vt1 = getDefaultTestInstance(); vt1.compareTo(null); } /** * Verifies that <code>Serializable</code> is implemented correctly. */ @Test(groups = { "api" }) public final void shouldImplementSerialization() { final ValueType<?> vt1 = getDefaultTestInstance(); final ValueType<?> vt2 = (ValueType<?>) SerializationUtils.deserialize(SerializationUtils.serialize(vt1)); assertEquals(vt2, vt1); } /** * Verifies that <code>toString</code> produces a unique value that enables a parser to identify the string as being * produced by this particular class. */ @Test(groups = { "api" }) public final void shouldOverrideStringWithUniquelyFormattedValue() { final ValueType<?> vt1 = getDefaultTestInstance(); assertFalse(vt1.toString().equals(ObjectUtils.identityToString(vt1))); doToStringTesting(); } /** * Abstract method which does additional <code>compareTo</code> testing. */ protected abstract void doCompareToTesting(); /** * Abstract method which does additional <code>equals</code> testing for non-equal instances of the class being * tested. */ protected abstract void doNonEqualsTesting(); /** * Abstract method which does additional testing of the <code>toString</code> method. */ protected abstract void doToStringTesting(); }