Enhanced assertions on thrown exceptions

Author: ndimiduk

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileBlockHeaderCorruption.java

@@ -18,20 +18,27 @@
 package org.apache.hadoop.hbase.io.hfile;
 
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.allOf;
+import static org.hamcrest.Matchers.hasProperty;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.startsWith;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
+import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.IOException;
+import java.io.PrintStream;
 import java.nio.ByteBuffer;
 import java.nio.channels.SeekableByteChannel;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
 import java.nio.file.StandardOpenOption;
 import java.time.Instant;
+import java.util.LinkedList;
+import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Random;
 import org.apache.hadoop.conf.Configuration;
@@ -47,7 +54,9 @@
 import org.apache.hadoop.hbase.testclassification.IOTests;
 import org.apache.hadoop.hbase.testclassification.SmallTests;
 import org.apache.hadoop.hbase.util.Bytes;
-import org.hamcrest.Matchers;
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
 import org.junit.ClassRule;
 import org.junit.Rule;
 import org.junit.Test;
@@ -106,8 +115,8 @@ public void testOnDiskSizeWithoutHeaderCorruptionFirstBlock() throws Exception {
           consumer.readFully();
           fail();
         } catch (Exception e) {
-          assertThat(e, instanceOf(IOException.class));
-          assertThat(e.getMessage(), startsWith("Invalid onDiskSizeWithHeader="));
+          assertThat(e, new IsThrowableMatching().withInstanceOf(IOException.class)
+            .withMessage(startsWith("Invalid onDiskSizeWithHeader=")));
         }
         assertEquals(0, consumer.getItemsRead());
       }
@@ -123,8 +132,8 @@ public void testOnDiskSizeWithoutHeaderCorruptionFirstBlock() throws Exception {
           consumer.readFully();
           fail();
         } catch (Exception e) {
-          assertThat(e, instanceOf(IllegalArgumentException.class));
-          assertThat(e.getMessage(), startsWith("newLimit > capacity"));
+          assertThat(e, new IsThrowableMatching().withInstanceOf(IllegalArgumentException.class)
+            .withMessage(startsWith("newLimit > capacity")));
         }
         assertEquals(0, consumer.getItemsRead());
       }
@@ -140,8 +149,8 @@ public void testOnDiskSizeWithoutHeaderCorruptionFirstBlock() throws Exception {
           consumer.readFully();
           fail();
         } catch (Exception e) {
-          assertThat(e, instanceOf(IOException.class));
-          assertThat(e.getMessage(), Matchers.startsWith("Invalid onDiskSizeWithHeader="));
+          assertThat(e, new IsThrowableMatching().withInstanceOf(IOException.class)
+            .withMessage(startsWith("Invalid onDiskSizeWithHeader=")));
         }
         assertEquals(0, consumer.getItemsRead());
       }
@@ -177,8 +186,8 @@ public void testOnDiskSizeWithoutHeaderCorruptionSecondBlock() throws Exception
           consumer.readFully();
           fail();
         } catch (Exception e) {
-          assertThat(e, instanceOf(IOException.class));
-          assertThat(e.getMessage(), Matchers.startsWith("Invalid onDiskSizeWithHeader="));
+          assertThat(e, new IsThrowableMatching().withInstanceOf(IOException.class)
+            .withMessage(startsWith("Invalid onDiskSizeWithHeader=")));
         }
         assertEquals(1, consumer.getItemsRead());
       }
@@ -194,8 +203,8 @@ public void testOnDiskSizeWithoutHeaderCorruptionSecondBlock() throws Exception
           consumer.readFully();
           fail();
         } catch (Exception e) {
-          assertTrue(e instanceof IllegalArgumentException);
-          assertTrue(e.getMessage().startsWith("newLimit > capacity"));
+          assertThat(e, new IsThrowableMatching().withInstanceOf(IllegalArgumentException.class)
+            .withMessage(startsWith("newLimit > capacity")));
         }
         assertEquals(1, consumer.getItemsRead());
       }
@@ -211,8 +220,8 @@ public void testOnDiskSizeWithoutHeaderCorruptionSecondBlock() throws Exception
           consumer.readFully();
           fail();
         } catch (Exception e) {
-          assertTrue(e instanceof IOException);
-          assertTrue(e.getMessage().startsWith("Invalid onDiskSizeWithHeader="));
+          assertThat(e, new IsThrowableMatching().withInstanceOf(IOException.class)
+            .withMessage(startsWith("Invalid onDiskSizeWithHeader=")));
         }
         assertEquals(1, consumer.getItemsRead());
       }
@@ -367,7 +376,7 @@ private interface CloseMethod {
       void run() throws IOException;
     }
 
-    private static <T extends Throwable> void closeQuietly(CloseMethod closeMethod) {
+    private static void closeQuietly(CloseMethod closeMethod) {
       try {
         closeMethod.run();
       } catch (Throwable e) {
@@ -474,4 +483,49 @@ protected void before() throws Throwable {
       }
     }
   }
+
+  /**
+   * A Matcher implementation that can make basic assertions over a provided {@link Throwable}.
+   * Assertion failures include the full stacktrace in their description.
+   */
+  private static final class IsThrowableMatching extends TypeSafeMatcher<Throwable> {
+
+    private final List<Matcher<? super Throwable>> requirements = new LinkedList<>();
+
+    public IsThrowableMatching withInstanceOf(Class<?> type) {
+      requirements.add(instanceOf(type));
+      return this;
+    }
+
+    public IsThrowableMatching withMessage(Matcher<String> matcher) {
+      requirements.add(hasProperty("message", matcher));
+      return this;
+    }
+
+    @Override
+    protected boolean matchesSafely(Throwable throwable) {
+      return allOf(requirements).matches(throwable);
+    }
+
+    @Override
+    protected void describeMismatchSafely(Throwable item, Description mismatchDescription) {
+      allOf(requirements).describeMismatch(item, mismatchDescription);
+      // would be nice if `item` could be provided as the cause of the AssertionError instead.
+      mismatchDescription.appendText(String.format("%nProvided: "));
+      try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
+        try (PrintStream ps = new PrintStream(baos, false, StandardCharsets.UTF_8.name())) {
+          item.printStackTrace(ps);
+          ps.flush();
+        }
+        mismatchDescription.appendText(baos.toString(StandardCharsets.UTF_8.name()));
+      } catch (Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+
+    @Override
+    public void describeTo(Description description) {
+      description.appendDescriptionOf(allOf(requirements));
+    }
+  }
 }