diff options
Diffstat (limited to 'src/main/java/org/junit/internal/Throwables.java')
-rw-r--r-- | src/main/java/org/junit/internal/Throwables.java | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/src/main/java/org/junit/internal/Throwables.java b/src/main/java/org/junit/internal/Throwables.java index 86dceef..3f0f7a3 100644 --- a/src/main/java/org/junit/internal/Throwables.java +++ b/src/main/java/org/junit/internal/Throwables.java @@ -1,5 +1,17 @@ package org.junit.internal; +import java.io.BufferedReader; +import java.io.IOException; +import java.io.PrintWriter; +import java.io.StringReader; +import java.io.StringWriter; +import java.lang.reflect.Method; +import java.util.AbstractList; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.List; + /** * Miscellaneous functions dealing with {@code Throwable}. * @@ -39,4 +51,223 @@ public final class Throwables { private static <T extends Throwable> void rethrow(Throwable e) throws T { throw (T) e; } + + /** + * Returns the stacktrace of the given Throwable as a String. + * + * @since 4.13 + */ + public static String getStacktrace(Throwable exception) { + StringWriter stringWriter = new StringWriter(); + PrintWriter writer = new PrintWriter(stringWriter); + exception.printStackTrace(writer); + return stringWriter.toString(); + } + + /** + * Gets a trimmed version of the stack trace of the given exception. Stack trace + * elements that are below the test method are filtered out. + * + * @return a trimmed stack trace, or the original trace if trimming wasn't possible + */ + public static String getTrimmedStackTrace(Throwable exception) { + List<String> trimmedStackTraceLines = getTrimmedStackTraceLines(exception); + if (trimmedStackTraceLines.isEmpty()) { + return getFullStackTrace(exception); + } + + StringBuilder result = new StringBuilder(exception.toString()); + appendStackTraceLines(trimmedStackTraceLines, result); + appendStackTraceLines(getCauseStackTraceLines(exception), result); + return result.toString(); + } + + private static List<String> getTrimmedStackTraceLines(Throwable exception) { + List<StackTraceElement> stackTraceElements = Arrays.asList(exception.getStackTrace()); + int linesToInclude = stackTraceElements.size(); + + State state = State.PROCESSING_OTHER_CODE; + for (StackTraceElement stackTraceElement : asReversedList(stackTraceElements)) { + state = state.processStackTraceElement(stackTraceElement); + if (state == State.DONE) { + List<String> trimmedLines = new ArrayList<String>(linesToInclude + 2); + trimmedLines.add(""); + for (StackTraceElement each : stackTraceElements.subList(0, linesToInclude)) { + trimmedLines.add("\tat " + each); + } + if (exception.getCause() != null) { + trimmedLines.add("\t... " + (stackTraceElements.size() - trimmedLines.size()) + " trimmed"); + } + return trimmedLines; + } + linesToInclude--; + } + return Collections.emptyList(); + } + + private static final Method getSuppressed = initGetSuppressed(); + + private static Method initGetSuppressed() { + try { + return Throwable.class.getMethod("getSuppressed"); + } catch (Throwable e) { + return null; + } + } + + private static boolean hasSuppressed(Throwable exception) { + if (getSuppressed == null) { + return false; + } + try { + Throwable[] suppressed = (Throwable[]) getSuppressed.invoke(exception); + return suppressed.length != 0; + } catch (Throwable e) { + return false; + } + } + + private static List<String> getCauseStackTraceLines(Throwable exception) { + if (exception.getCause() != null || hasSuppressed(exception)) { + String fullTrace = getFullStackTrace(exception); + BufferedReader reader = new BufferedReader( + new StringReader(fullTrace.substring(exception.toString().length()))); + List<String> causedByLines = new ArrayList<String>(); + + try { + String line; + while ((line = reader.readLine()) != null) { + if (line.startsWith("Caused by: ") || line.trim().startsWith("Suppressed: ")) { + causedByLines.add(line); + while ((line = reader.readLine()) != null) { + causedByLines.add(line); + } + return causedByLines; + } + } + } catch (IOException e) { + // We should never get here, because we are reading from a StringReader + } + } + + return Collections.emptyList(); + } + + private static String getFullStackTrace(Throwable exception) { + StringWriter stringWriter = new StringWriter(); + PrintWriter writer = new PrintWriter(stringWriter); + exception.printStackTrace(writer); + return stringWriter.toString(); + } + + private static void appendStackTraceLines( + List<String> stackTraceLines, StringBuilder destBuilder) { + for (String stackTraceLine : stackTraceLines) { + destBuilder.append(String.format("%s%n", stackTraceLine)); + } + } + + private static <T> List<T> asReversedList(final List<T> list) { + return new AbstractList<T>() { + + @Override + public T get(int index) { + return list.get(list.size() - index - 1); + } + + @Override + public int size() { + return list.size(); + } + }; + } + + private enum State { + PROCESSING_OTHER_CODE { + @Override public State processLine(String methodName) { + if (isTestFrameworkMethod(methodName)) { + return PROCESSING_TEST_FRAMEWORK_CODE; + } + return this; + } + }, + PROCESSING_TEST_FRAMEWORK_CODE { + @Override public State processLine(String methodName) { + if (isReflectionMethod(methodName)) { + return PROCESSING_REFLECTION_CODE; + } else if (isTestFrameworkMethod(methodName)) { + return this; + } + return PROCESSING_OTHER_CODE; + } + }, + PROCESSING_REFLECTION_CODE { + @Override public State processLine(String methodName) { + if (isReflectionMethod(methodName)) { + return this; + } else if (isTestFrameworkMethod(methodName)) { + // This is here to handle TestCase.runBare() calling TestCase.runTest(). + return PROCESSING_TEST_FRAMEWORK_CODE; + } + return DONE; + } + }, + DONE { + @Override public State processLine(String methodName) { + return this; + } + }; + + /** Processes a stack trace element method name, possibly moving to a new state. */ + protected abstract State processLine(String methodName); + + /** Processes a stack trace element, possibly moving to a new state. */ + public final State processStackTraceElement(StackTraceElement element) { + return processLine(element.getClassName() + "." + element.getMethodName() + "()"); + } + } + + private static final String[] TEST_FRAMEWORK_METHOD_NAME_PREFIXES = { + "org.junit.runner.", + "org.junit.runners.", + "org.junit.experimental.runners.", + "org.junit.internal.", + "junit.extensions", + "junit.framework", + "junit.runner", + "junit.textui", + }; + + private static final String[] TEST_FRAMEWORK_TEST_METHOD_NAME_PREFIXES = { + "org.junit.internal.StackTracesTest", + }; + + private static boolean isTestFrameworkMethod(String methodName) { + return isMatchingMethod(methodName, TEST_FRAMEWORK_METHOD_NAME_PREFIXES) && + !isMatchingMethod(methodName, TEST_FRAMEWORK_TEST_METHOD_NAME_PREFIXES); + } + + private static final String[] REFLECTION_METHOD_NAME_PREFIXES = { + "sun.reflect.", + "java.lang.reflect.", + "jdk.internal.reflect.", + "org.junit.rules.RunRules.<init>(", + "org.junit.rules.RunRules.applyAll(", // calls TestRules + "org.junit.runners.RuleContainer.apply(", // calls MethodRules & TestRules + "junit.framework.TestCase.runBare(", // runBare() directly calls setUp() and tearDown() + }; + + private static boolean isReflectionMethod(String methodName) { + return isMatchingMethod(methodName, REFLECTION_METHOD_NAME_PREFIXES); + } + + private static boolean isMatchingMethod(String methodName, String[] methodNamePrefixes) { + for (String methodNamePrefix : methodNamePrefixes) { + if (methodName.startsWith(methodNamePrefix)) { + return true; + } + } + + return false; + } } |