001/*
002 * Copyright (C) 2012 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.testing;
018
019import static com.google.common.base.Predicates.and;
020import static com.google.common.base.Predicates.not;
021import static com.google.common.testing.AbstractPackageSanityTests.Chopper.suffix;
022
023import com.google.common.annotations.Beta;
024import com.google.common.annotations.GwtIncompatible;
025import com.google.common.annotations.VisibleForTesting;
026import com.google.common.base.Optional;
027import com.google.common.base.Predicate;
028import com.google.common.collect.HashMultimap;
029import com.google.common.collect.ImmutableList;
030import com.google.common.collect.Iterables;
031import com.google.common.collect.Lists;
032import com.google.common.collect.Maps;
033import com.google.common.collect.Multimap;
034import com.google.common.collect.Sets;
035import com.google.common.reflect.ClassPath;
036import com.google.common.testing.NullPointerTester.Visibility;
037import com.google.j2objc.annotations.J2ObjCIncompatible;
038import java.io.IOException;
039import java.io.Serializable;
040import java.util.LinkedHashSet;
041import java.util.List;
042import java.util.Locale;
043import java.util.TreeMap;
044import java.util.logging.Level;
045import java.util.logging.Logger;
046import junit.framework.AssertionFailedError;
047import junit.framework.TestCase;
048import org.junit.Test;
049
050/**
051 * Automatically runs sanity checks against top level classes in the same package of the test that
052 * extends {@code AbstractPackageSanityTests}. Currently sanity checks include {@link
053 * NullPointerTester}, {@link EqualsTester} and {@link SerializableTester}. For example:
054 *
055 * <pre>
056 * public class PackageSanityTests extends AbstractPackageSanityTests {}
057 * </pre>
058 *
059 * <p>Note that only top-level classes with either a non-private constructor or a non-private static
060 * factory method to construct instances can have their instance methods checked. For example:
061 *
062 * <pre>
063 * public class Address {
064 *   private final String city;
065 *   private final String state;
066 *   private final String zipcode;
067 *
068 *   public Address(String city, String state, String zipcode) {...}
069 *
070 *   {@literal @Override} public boolean equals(Object obj) {...}
071 *   {@literal @Override} public int hashCode() {...}
072 *   ...
073 * }
074 * </pre>
075 *
076 * <p>No cascading checks are performed against the return values of methods unless the method is a
077 * static factory method. Neither are semantics of mutation methods such as {@code
078 * someList.add(obj)} checked. For more detailed discussion of supported and unsupported cases, see
079 * {@link #testEquals}, {@link #testNulls} and {@link #testSerializable}.
080 *
081 * <p>For testing against the returned instances from a static factory class, such as
082 *
083 * <pre>
084 * interface Book {...}
085 * public class Books {
086 *   public static Book hardcover(String title) {...}
087 *   public static Book paperback(String title) {...}
088 * }
089 * </pre>
090 *
091 * <p>please use {@link ClassSanityTester#forAllPublicStaticMethods}.
092 *
093 * <p>If not all classes on the classpath should be covered, {@link #ignoreClasses} can be used to
094 * exclude certain classes. As a special case, classes with an underscore in the name (like {@code
095 * AutoValue_Foo}) can be excluded using <code>ignoreClasses({@link #UNDERSCORE_IN_NAME})</code>.
096 *
097 * <p>{@link #setDefault} allows subclasses to specify default values for types.
098 *
099 * <p>This class incurs IO because it scans the classpath and reads classpath resources.
100 *
101 * @author Ben Yu
102 * @since 14.0
103 */
104@Beta
105// TODO: Switch to JUnit 4 and use @Parameterized and @BeforeClass
106// Note: @Test annotations are deliberate, as some subclasses specify @RunWith(JUnit4).
107@GwtIncompatible
108@J2ObjCIncompatible // com.google.common.reflect.ClassPath
109public abstract class AbstractPackageSanityTests extends TestCase {
110
111  /**
112   * A predicate that matches classes with an underscore in the class name. This can be used with
113   * {@link #ignoreClasses} to exclude generated classes, such as the {@code AutoValue_Foo} classes
114   * generated by <a href="https://github.com/google/auto/tree/master/value">AutoValue</a>.
115   *
116   * @since 19.0
117   */
118  public static final Predicate<Class<?>> UNDERSCORE_IN_NAME =
119      (Class<?> c) -> c.getSimpleName().contains("_");
120
121  /* The names of the expected method that tests null checks. */
122  private static final ImmutableList<String> NULL_TEST_METHOD_NAMES =
123      ImmutableList.of(
124          "testNulls", "testNull",
125          "testNullPointers", "testNullPointer",
126          "testNullPointerExceptions", "testNullPointerException");
127
128  /* The names of the expected method that tests serializable. */
129  private static final ImmutableList<String> SERIALIZABLE_TEST_METHOD_NAMES =
130      ImmutableList.of(
131          "testSerializable", "testSerialization",
132          "testEqualsAndSerializable", "testEqualsAndSerialization");
133
134  /* The names of the expected method that tests equals. */
135  private static final ImmutableList<String> EQUALS_TEST_METHOD_NAMES =
136      ImmutableList.of(
137          "testEquals",
138          "testEqualsAndHashCode",
139          "testEqualsAndSerializable",
140          "testEqualsAndSerialization",
141          "testEquality");
142
143  private static final Chopper TEST_SUFFIX =
144      suffix("Test").or(suffix("Tests")).or(suffix("TestCase")).or(suffix("TestSuite"));
145
146  private final Logger logger = Logger.getLogger(getClass().getName());
147  private final ClassSanityTester tester = new ClassSanityTester();
148  private Visibility visibility = Visibility.PACKAGE;
149  private Predicate<Class<?>> classFilter =
150      (Class<?> cls) -> visibility.isVisible(cls.getModifiers());
151
152  /**
153   * Restricts the sanity tests for public API only. By default, package-private API are also
154   * covered.
155   */
156  protected final void publicApiOnly() {
157    visibility = Visibility.PUBLIC;
158  }
159
160  /**
161   * Tests all top-level {@link Serializable} classes in the package. For a serializable Class
162   * {@code C}:
163   *
164   * <ul>
165   *   <li>If {@code C} explicitly implements {@link Object#equals}, the deserialized instance will
166   *       be checked to be equal to the instance before serialization.
167   *   <li>If {@code C} doesn't explicitly implement {@code equals} but instead inherits it from a
168   *       superclass, no equality check is done on the deserialized instance because it's not clear
169   *       whether the author intended for the class to be a value type.
170   *   <li>If a constructor or factory method takes a parameter whose type is interface, a dynamic
171   *       proxy will be passed to the method. It's possible that the method body expects an
172   *       instance method of the passed-in proxy to be of a certain value yet the proxy isn't aware
173   *       of the assumption, in which case the equality check before and after serialization will
174   *       fail.
175   *   <li>If the constructor or factory method takes a parameter that {@link
176   *       AbstractPackageSanityTests} doesn't know how to construct, the test will fail.
177   *   <li>If there is no visible constructor or visible static factory method declared by {@code
178   *       C}, {@code C} is skipped for serialization test, even if it implements {@link
179   *       Serializable}.
180   *   <li>Serialization test is not performed on method return values unless the method is a
181   *       visible static factory method whose return type is {@code C} or {@code C}'s subtype.
182   * </ul>
183   *
184   * <p>In all cases, if {@code C} needs custom logic for testing serialization, you can add an
185   * explicit {@code testSerializable()} test in the corresponding {@code CTest} class, and {@code
186   * C} will be excluded from automated serialization test performed by this method.
187   */
188  @Test
189  public void testSerializable() throws Exception {
190    // TODO: when we use @BeforeClass, we can pay the cost of class path scanning only once.
191    for (Class<?> classToTest :
192        findClassesToTest(loadClassesInPackage(), SERIALIZABLE_TEST_METHOD_NAMES)) {
193      if (Serializable.class.isAssignableFrom(classToTest)) {
194        try {
195          Object instance = tester.instantiate(classToTest);
196          if (instance != null) {
197            if (isEqualsDefined(classToTest)) {
198              SerializableTester.reserializeAndAssert(instance);
199            } else {
200              SerializableTester.reserialize(instance);
201            }
202          }
203        } catch (Throwable e) {
204          throw sanityError(classToTest, SERIALIZABLE_TEST_METHOD_NAMES, "serializable test", e);
205        }
206      }
207    }
208  }
209
210  /**
211   * Performs {@link NullPointerTester} checks for all top-level classes in the package. For a class
212   * {@code C}
213   *
214   * <ul>
215   *   <li>All visible static methods are checked such that passing null for any parameter that's
216   *       not annotated nullable (according to the rules of {@link NullPointerTester}) should throw
217   *       {@link NullPointerException}.
218   *   <li>If there is any visible constructor or visible static factory method declared by the
219   *       class, all visible instance methods will be checked too using the instance created by
220   *       invoking the constructor or static factory method.
221   *   <li>If the constructor or factory method used to construct instance takes a parameter that
222   *       {@link AbstractPackageSanityTests} doesn't know how to construct, the test will fail.
223   *   <li>If there is no visible constructor or visible static factory method declared by {@code
224   *       C}, instance methods are skipped for nulls test.
225   *   <li>Nulls test is not performed on method return values unless the method is a visible static
226   *       factory method whose return type is {@code C} or {@code C}'s subtype.
227   * </ul>
228   *
229   * <p>In all cases, if {@code C} needs custom logic for testing nulls, you can add an explicit
230   * {@code testNulls()} test in the corresponding {@code CTest} class, and {@code C} will be
231   * excluded from the automated null tests performed by this method.
232   */
233  @Test
234  public void testNulls() throws Exception {
235    for (Class<?> classToTest : findClassesToTest(loadClassesInPackage(), NULL_TEST_METHOD_NAMES)) {
236      try {
237        tester.doTestNulls(classToTest, visibility);
238      } catch (Throwable e) {
239        throw sanityError(classToTest, NULL_TEST_METHOD_NAMES, "nulls test", e);
240      }
241    }
242  }
243
244  /**
245   * Tests {@code equals()} and {@code hashCode()} implementations for every top-level class in the
246   * package, that explicitly implements {@link Object#equals}. For a class {@code C}:
247   *
248   * <ul>
249   *   <li>The visible constructor or visible static factory method with the most parameters is used
250   *       to construct the sample instances. In case of tie, the candidate constructors or
251   *       factories are tried one after another until one can be used to construct sample
252   *       instances.
253   *   <li>For the constructor or static factory method used to construct instances, it's checked
254   *       that when equal parameters are passed, the result instance should also be equal; and vice
255   *       versa.
256   *   <li>Inequality check is not performed against state mutation methods such as {@link
257   *       List#add}, or functional update methods such as {@link
258   *       com.google.common.base.Joiner#skipNulls}.
259   *   <li>If the constructor or factory method used to construct instance takes a parameter that
260   *       {@link AbstractPackageSanityTests} doesn't know how to construct, the test will fail.
261   *   <li>If there is no visible constructor or visible static factory method declared by {@code
262   *       C}, {@code C} is skipped for equality test.
263   *   <li>Equality test is not performed on method return values unless the method is a visible
264   *       static factory method whose return type is {@code C} or {@code C}'s subtype.
265   * </ul>
266   *
267   * <p>In all cases, if {@code C} needs custom logic for testing {@code equals()}, you can add an
268   * explicit {@code testEquals()} test in the corresponding {@code CTest} class, and {@code C} will
269   * be excluded from the automated {@code equals} test performed by this method.
270   */
271  @Test
272  public void testEquals() throws Exception {
273    for (Class<?> classToTest :
274        findClassesToTest(loadClassesInPackage(), EQUALS_TEST_METHOD_NAMES)) {
275      if (!classToTest.isEnum() && isEqualsDefined(classToTest)) {
276        try {
277          tester.doTestEquals(classToTest);
278        } catch (Throwable e) {
279          throw sanityError(classToTest, EQUALS_TEST_METHOD_NAMES, "equals test", e);
280        }
281      }
282    }
283  }
284
285  /**
286   * Sets the default value for {@code type}, when dummy value for a parameter of the same type
287   * needs to be created in order to invoke a method or constructor. The default value isn't used in
288   * testing {@link Object#equals} because more than one sample instances are needed for testing
289   * inequality.
290   */
291  protected final <T> void setDefault(Class<T> type, T value) {
292    tester.setDefault(type, value);
293  }
294
295  /**
296   * Sets two distinct values for {@code type}. These values can be used for both null pointer
297   * testing and equals testing.
298   *
299   * @since 17.0
300   */
301  protected final <T> void setDistinctValues(Class<T> type, T value1, T value2) {
302    tester.setDistinctValues(type, value1, value2);
303  }
304
305  /** Specifies that classes that satisfy the given predicate aren't tested for sanity. */
306  protected final void ignoreClasses(Predicate<? super Class<?>> condition) {
307    this.classFilter = and(this.classFilter, not(condition));
308  }
309
310  private static AssertionFailedError sanityError(
311      Class<?> cls, List<String> explicitTestNames, String description, Throwable e) {
312    String message =
313        String.format(
314            Locale.ROOT,
315            "Error in automated %s of %s\n"
316                + "If the class is better tested explicitly, you can add %s() to %sTest",
317            description,
318            cls,
319            explicitTestNames.get(0),
320            cls.getName());
321    AssertionFailedError error = new AssertionFailedError(message);
322    error.initCause(e);
323    return error;
324  }
325
326  /**
327   * Finds the classes not ending with a test suffix and not covered by an explicit test whose name
328   * is {@code explicitTestName}.
329   */
330  @VisibleForTesting
331  List<Class<?>> findClassesToTest(
332      Iterable<? extends Class<?>> classes, Iterable<String> explicitTestNames) {
333    // "a.b.Foo" -> a.b.Foo.class
334    TreeMap<String, Class<?>> classMap = Maps.newTreeMap();
335    for (Class<?> cls : classes) {
336      classMap.put(cls.getName(), cls);
337    }
338    // Foo.class -> [FooTest.class, FooTests.class, FooTestSuite.class, ...]
339    Multimap<Class<?>, Class<?>> testClasses = HashMultimap.create();
340    LinkedHashSet<Class<?>> candidateClasses = Sets.newLinkedHashSet();
341    for (Class<?> cls : classes) {
342      Optional<String> testedClassName = TEST_SUFFIX.chop(cls.getName());
343      if (testedClassName.isPresent()) {
344        Class<?> testedClass = classMap.get(testedClassName.get());
345        if (testedClass != null) {
346          testClasses.put(testedClass, cls);
347        }
348      } else {
349        candidateClasses.add(cls);
350      }
351    }
352    List<Class<?>> result = Lists.newArrayList();
353    NEXT_CANDIDATE:
354    for (Class<?> candidate : Iterables.filter(candidateClasses, classFilter)) {
355      for (Class<?> testClass : testClasses.get(candidate)) {
356        if (hasTest(testClass, explicitTestNames)) {
357          // covered by explicit test
358          continue NEXT_CANDIDATE;
359        }
360      }
361      result.add(candidate);
362    }
363    return result;
364  }
365
366  private List<Class<?>> loadClassesInPackage() throws IOException {
367    List<Class<?>> classes = Lists.newArrayList();
368    String packageName = getClass().getPackage().getName();
369    for (ClassPath.ClassInfo classInfo :
370        ClassPath.from(getClass().getClassLoader()).getTopLevelClasses(packageName)) {
371      Class<?> cls;
372      try {
373        cls = classInfo.load();
374      } catch (NoClassDefFoundError e) {
375        // In case there were linking problems, this is probably not a class we care to test anyway.
376        logger.log(Level.SEVERE, "Cannot load class " + classInfo + ", skipping...", e);
377        continue;
378      }
379      if (!cls.isInterface()) {
380        classes.add(cls);
381      }
382    }
383    return classes;
384  }
385
386  private static boolean hasTest(Class<?> testClass, Iterable<String> testNames) {
387    for (String testName : testNames) {
388      try {
389        testClass.getMethod(testName);
390        return true;
391      } catch (NoSuchMethodException e) {
392        continue;
393      }
394    }
395    return false;
396  }
397
398  private static boolean isEqualsDefined(Class<?> cls) {
399    try {
400      return !cls.getDeclaredMethod("equals", Object.class).isSynthetic();
401    } catch (NoSuchMethodException e) {
402      return false;
403    }
404  }
405
406  abstract static class Chopper {
407
408    final Chopper or(Chopper you) {
409      Chopper i = this;
410      return new Chopper() {
411        @Override
412        Optional<String> chop(String str) {
413          return i.chop(str).or(you.chop(str));
414        }
415      };
416    }
417
418    abstract Optional<String> chop(String str);
419
420    static Chopper suffix(String suffix) {
421      return new Chopper() {
422        @Override
423        Optional<String> chop(String str) {
424          if (str.endsWith(suffix)) {
425            return Optional.of(str.substring(0, str.length() - suffix.length()));
426          } else {
427            return Optional.absent();
428          }
429        }
430      };
431    }
432  }
433}