Index: test/org/jmock/test/acceptance/junit4/testdata/JUnit4TestThatDoesNotDeclareAMockery.java
===================================================================
--- test/org/jmock/test/acceptance/junit4/testdata/JUnit4TestThatDoesNotDeclareAMockery.java	Fri Mar 20 16:41:39 GMT 2009
+++ test/org/jmock/test/acceptance/junit4/testdata/JUnit4TestThatDoesNotDeclareAMockery.java	Fri Mar 20 16:41:39 GMT 2009
@@ -0,0 +1,16 @@
+package org.jmock.test.acceptance.junit4.testdata;
+
+import org.junit.runner.RunWith;
+import org.junit.Test;
+import org.jmock.integration.junit4.JMock;
+
+/**
+ * JUnitTestThatDoesNotDeclareAMockery
+ */
+@RunWith(JMock.class)
+public class JUnit4TestThatDoesNotDeclareAMockery {
+
+    @Test
+    public void aTest() {
+    }
+}
Index: test/org/jmock/test/acceptance/junit4/testdata/JUnit4TestThatDeclaresMultipleMockeries.java
===================================================================
--- test/org/jmock/test/acceptance/junit4/testdata/JUnit4TestThatDeclaresMultipleMockeries.java	Fri Mar 20 16:18:50 GMT 2009
+++ test/org/jmock/test/acceptance/junit4/testdata/JUnit4TestThatDeclaresMultipleMockeries.java	Fri Mar 20 16:18:50 GMT 2009
@@ -0,0 +1,34 @@
+package org.jmock.test.acceptance.junit4.testdata;
+
+import org.jmock.Mockery;
+import org.jmock.Expectations;
+import org.jmock.integration.junit4.JUnit4Mockery;
+import org.jmock.integration.junit4.JMock;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * JUnit4TestThatDeclaresMultipleMockeries
+ */
+@RunWith(JMock.class)
+public class JUnit4TestThatDeclaresMultipleMockeries {
+
+    protected Mockery context1 = new JUnit4Mockery();
+    protected Mockery context2 = new JUnit4Mockery();
+    private Runnable runnable1 = context1.mock(Runnable.class);
+    private Runnable runnable2 = context2.mock(Runnable.class);
+
+    @Test
+    public void doesNotSatisfyExpectations() {
+        context1.checking(new Expectations() {{
+            oneOf (runnable1).run();
+        }});
+
+        context2.checking(new Expectations() {{
+            oneOf (runnable2).run();
+        }});
+
+        runnable1.run();
+    }
+
+}
Index: test/org/jmock/test/acceptance/junit4/JUnit4TestRunnerTests.java
===================================================================
--- test/org/jmock/test/acceptance/junit4/JUnit4TestRunnerTests.java	(revision 1351)
+++ test/org/jmock/test/acceptance/junit4/JUnit4TestRunnerTests.java	Fri Mar 20 16:56:22 GMT 2009
@@ -2,12 +2,7 @@
 
 import junit.framework.TestCase;
 
-import org.jmock.test.acceptance.junit4.testdata.DerivedJUnit4TestThatDoesNotSatisfyExpectations;
-import org.jmock.test.acceptance.junit4.testdata.JUnit4TestThatDoesNotCreateAMockery;
-import org.jmock.test.acceptance.junit4.testdata.JUnit4TestThatDoesNotSatisfyExpectations;
-import org.jmock.test.acceptance.junit4.testdata.JUnit4TestThatDoesSatisfyExpectations;
-import org.jmock.test.acceptance.junit4.testdata.JUnit4TestThatThrowsExpectedException;
-import org.jmock.test.acceptance.junit4.testdata.JUnit4TestWithNonPublicBeforeMethod;
+import org.jmock.test.acceptance.junit4.testdata.*;
 import org.jmock.test.unit.support.AssertThat;
 import org.junit.runner.Request;
 import org.junit.runner.Runner;
@@ -40,7 +35,20 @@
         runTest(JUnit4TestThatDoesNotCreateAMockery.class);
         assertTestFailedWith(IllegalStateException.class);
     }
-    
+
+    public void testTheJUnit4TestRunnerReportsAHelpfulErrorIfThereAreMultipleMockeries() {
+        runTest(JUnit4TestThatDeclaresMultipleMockeries.class);
+        assertTestFailedWith(Exception.class);
+        AssertThat.stringIncludes("Should warn of multiple mockeries", "multiple Mockeries", listener.failure.getMessage());
+    }
+
+    public void testTheJUnit4TestRunnerReportsAHelpfulErrorIfThereIsNoMockery() {
+        runTest(JUnit4TestThatDoesNotDeclareAMockery.class);
+        assertTestFailedWith(Exception.class);
+
+        AssertThat.stringIncludes("Should warn of missing mockery", "no Mockery", listener.failure.getMessage());
+    }
+
     // See issue JMOCK-156
     public void testReportsMocksAreNotSatisfiedWhenExpectedExceptionIsThrown() {
         runTest(JUnit4TestThatThrowsExpectedException.class);
@@ -53,13 +61,14 @@
         AssertThat.stringIncludes("should have detected non-public before method", 
                                   "Method before() should be public", listener.failure.getMessage());
     }
-    
+
     private void assertTestFailedWith(Class<? extends Throwable> exceptionType) {
         assertNotNull("test should have failed", listener.failure);
         assertTrue("should have failed with " + exceptionType.getName() + " but threw " + listener.failure.getException(), 
                    exceptionType.isInstance(listener.failure.getException()));
     }
-    
+
+
     private void runTest(Class<?> testClass) {
         Runner runner = Request.aClass(testClass).getRunner();
         RunNotifier notifier = new RunNotifier();
Index: src/org/jmock/integration/junit4/JMock.java
===================================================================
--- src/org/jmock/integration/junit4/JMock.java	(revision 1351)
+++ src/org/jmock/integration/junit4/JMock.java	Fri Mar 20 16:45:41 GMT 2009
@@ -1,6 +1,8 @@
 package org.jmock.integration.junit4;
 
 import java.lang.reflect.Field;
+import java.util.List;
+import java.util.ArrayList;
 
 import org.jmock.Mockery;
 import org.junit.runner.Runner;
@@ -64,14 +66,27 @@
     }
     
     static Field findMockeryField(Class<?> testClass) throws InitializationError {
+        List<Field> mockeryFields = getMockeriesForClass(testClass);
+
+        if (mockeryFields.isEmpty()){
+            throw new InitializationError("no Mockery found in test class " + testClass);
+        } else if (mockeryFields.size() != 1){
+            throw new InitializationError("multiple Mockeries found in test class " + testClass);
+        }
+
+        return mockeryFields.get(0);
+    }
+
+    private static List<Field> getMockeriesForClass(Class<?> testClass) {
+        List<Field> mockeryFields = new ArrayList<Field>();
+
         for (Class<?> c = testClass; c != Object.class; c = c.getSuperclass()) {
             for (Field field: c.getDeclaredFields()) {
                 if (Mockery.class.isAssignableFrom(field.getType())) {
-                    return field;
+                    mockeryFields.add(field);
                 }
             }
         }
-        
-        throw new InitializationError("no Mockery found in test class " + testClass);
+        return mockeryFields;
     }
 }