BREAKING: junit: Use relative resource paths with @DictionaryFile

The resource path is now interpreted relative to the class using the
annotation, which is more idiomatic. This does require changing
`com/example/Foo` to `/com/example/Foo` if an absolute path is desired.

Author: fmeum

examples/junit/src/test/java/com/example/DictionaryFuzzTests.java

@@ -43,7 +43,7 @@ public void inlineTest(FuzzedDataProvider data)
     }
   }
 
-  @DictionaryFile(resourcePath = "com/example/test.dict")
+  @DictionaryFile(resourcePath = "test.dict")
   @FuzzTest
   public void fileTest(FuzzedDataProvider data)
       throws NoSuchAlgorithmException, TestSuccessfulException {
@@ -55,8 +55,8 @@ public void fileTest(FuzzedDataProvider data)
   }
 
   @DictionaryEntries(tokens = {"a_"})
-  @DictionaryFile(resourcePath = "com/example/test2.dict")
-  @DictionaryFile(resourcePath = "com/example/test3.dict")
+  @DictionaryFile(resourcePath = "test2.dict")
+  @DictionaryFile(resourcePath = "/com/example/test3.dict")
   @FuzzTest
   public void mixedTest(FuzzedDataProvider data)
       throws NoSuchAlgorithmException, TestSuccessfulException {

examples/junit/src/test/resources/com/example/test.dict

@@ -1,4 +1,4 @@
 # test dictionary
 "a_"
-"53Cr3T_"
+"53Cr\"3T_"
 "fl4G"

examples/junit/src/test/resources/com/example/test2.dict

@@ -1 +1 @@
-"53Cr3T_"
+"53Cr\"3T_"

src/main/java/com/code_intelligence/jazzer/junit/DictionaryFile.java

@@ -23,13 +23,13 @@
 import java.lang.annotation.Target;
 
 /**
- * Defines a reference to a dictionary within the resources directory. The given {@code
- * resourcePath} must be an absolute path and must not have a leading {@code /}. These should follow
- * <a href="https://llvm.org/docs/LibFuzzer.html#dictionaries">libfuzzer's dictionary syntax</a>.
+ * Attaches a dictionary file located in resources to a fuzz test. The file should follow <a
+ * href="https://llvm.org/docs/LibFuzzer.html#dictionaries">libfuzzer's dictionary syntax</a>.
  */
 @Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
 @Retention(RetentionPolicy.RUNTIME)
 @Repeatable(DictionaryFiles.class)
 public @interface DictionaryFile {
+  /** The resource path of the dictionary file. */
   String resourcePath();
 }

src/main/java/com/code_intelligence/jazzer/junit/FuzzerDictionary.java

@@ -65,7 +65,8 @@ static Optional<Path> createDictionaryFile(Method method) throws IOException {
     List<DictionaryFile> fileDictionaries =
         AnnotationSupport.findRepeatableAnnotations(method, DictionaryFile.class);
 
-    return FuzzerDictionary.createDictionaryFile(inlineDictionaries, fileDictionaries);
+    return FuzzerDictionary.createDictionaryFile(
+        inlineDictionaries, fileDictionaries, method.getDeclaringClass());
   }
 
   /**
@@ -74,17 +75,20 @@ static Optional<Path> createDictionaryFile(Method method) throws IOException {
    *
    * @param inline list of {@link DictionaryEntries}
    * @param files list of {@link DictionaryFile}
+   * @param declaringClass class containing the method with these annotations
    * @return Optional of dictionaryPath if created
    * @throws IOException
    */
   private static Optional<Path> createDictionaryFile(
-      List<DictionaryEntries> inline, List<DictionaryFile> files) throws IOException {
+      List<DictionaryEntries> inline, List<DictionaryFile> files, Class<?> declaringClass)
+      throws IOException {
     int sources = inline.size() + files.size();
     if (sources == 0) {
       return Optional.empty();
     }
 
-    Stream<String> joined = Stream.concat(getInlineTokens(inline), getFileTokens(files));
+    Stream<String> joined =
+        Stream.concat(getInlineTokens(inline), getFileTokens(files, declaringClass));
 
     Path p = Files.createTempFile(DICTIONARY_PREFIX, DICTIONARY_SUFFIX);
     p.toFile().deleteOnExit();
@@ -120,26 +124,21 @@ private static Stream<String> getInlineTokens(List<DictionaryEntries> inline) {
   /**
    * Gets the individual lines from each of the specified dictionary files
    *
-   * @param files List of {@link DictionaryFile} annotations indicating which files to use
+   * @param files list of {@link DictionaryFile} annotations indicating which files to use
+   * @param declaringClass class containing the method with these annotations
    * @return stream of all lines from each of the files
    */
-  private static Stream<String> getFileTokens(List<DictionaryFile> files) {
+  private static Stream<String> getFileTokens(List<DictionaryFile> files, Class<?> declaringClass) {
     return files.stream()
         .map(DictionaryFile::resourcePath)
-        .map(FuzzerDictionary::tokensFromResource)
+        .map(resourcePath -> tokensFromResource(resourcePath, declaringClass))
         .flatMap(List::stream);
   }
 
-  private static List<String> tokensFromResource(String absoluteResourcePath) {
-    if (absoluteResourcePath.startsWith("/")) {
-      throw new IllegalArgumentException(
-          String.format(
-              "absolute resource path is must not have leading /: %s", absoluteResourcePath));
-    }
-    try (InputStream resourceFile =
-        FuzzerDictionary.class.getClassLoader().getResourceAsStream(absoluteResourcePath)) {
+  private static List<String> tokensFromResource(String resourcePath, Class<?> declaringClass) {
+    try (InputStream resourceFile = declaringClass.getResourceAsStream(resourcePath)) {
       if (resourceFile == null) {
-        throw new FileNotFoundException(absoluteResourcePath);
+        throw new FileNotFoundException(resourcePath);
       }
       List<String> tokens;
       try (BufferedReader reader = new BufferedReader(new InputStreamReader(resourceFile))) {