1 files changed, 45 insertions, 0 deletions
diff --git a/src/org/junit/rules/Verifier.java b/src/org/junit/rules/Verifier.java
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+++ b/src/org/junit/rules/Verifier.java
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+package org.junit.rules;
+
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+/**
+ * Verifier is a base class for Rules like ErrorCollector, which can turn
+ * otherwise passing test methods into failing tests if a verification check is
+ * failed
+ * 
+ * <pre>
+ *     public static class ErrorLogVerifier() {
+ *        private ErrorLog errorLog = new ErrorLog();
+ *     
+ *        &#064;Rule
+ *        public MethodRule verifier = new Verifier() {
+ *           &#064;Override public void verify() {
+ *              assertTrue(errorLog.isEmpty());
+ *           }
+ *        }
+ *        
+ *        &#064;Test public void testThatMightWriteErrorLog() {
+ *           // ...
+ *        }
+ *     }
+ * </pre>
+ */
+public class Verifier implements TestRule {
+	public Statement apply(final Statement base, Description description) {
+		return new Statement() {
+			@Override
+			public void evaluate() throws Throwable {
+				base.evaluate();
+				verify();
+			}
+		};
+	}
+
+	/**
+	 * Override this to add verification logic. Overrides should throw an
+	 * exception to indicate that verification failed.
+	 */
+	protected void verify() throws Throwable {
+	}
+}