1.x: TestSubscriber extra info on assertion failures

src/main/java/rx/observers/TestObserver.java

@@ -15,12 +15,11 @@
  */
 package rx.observers;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 
 import rx.Notification;
 import rx.Observer;
+import rx.exceptions.CompositeException;
 
 /**
  * Observer usable for unit testing to perform assertions, inspect received events or wrap a mocked Observer.
@@ -113,11 +112,12 @@ public List<Object> getEvents() {
      */
     public void assertReceivedOnNext(List<T> items) {
         if (onNextEvents.size() != items.size()) {
-            throw new AssertionError("Number of items does not match. Provided: " + items.size() + "  Actual: " + onNextEvents.size()
+            assertionError("Number of items does not match. Provided: " + items.size() + "  Actual: " + onNextEvents.size()
             + ".\n"
             + "Provided values: " + items
             + "\n"
-            + "Actual values: " + onNextEvents);
+            + "Actual values: " + onNextEvents
+            + "\n");
         }
 
         for (int i = 0; i < items.size(); i++) {
@@ -126,12 +126,12 @@ public void assertReceivedOnNext(List<T> items) {
             if (expected == null) {
                 // check for null equality
                 if (actual != null) {
-                    throw new AssertionError("Value at index: " + i + " expected to be [null] but was: [" + actual + "]");
+                    assertionError("Value at index: " + i + " expected to be [null] but was: [" + actual + "]\n");
                 }
             } else if (!expected.equals(actual)) {
-                throw new AssertionError("Value at index: " + i 
+                assertionError("Value at index: " + i 
                         + " expected to be [" + expected + "] (" + expected.getClass().getSimpleName() 
-                        + ") but was: [" + actual + "] (" + (actual != null ? actual.getClass().getSimpleName() : "null") + ")");
+                        + ") but was: [" + actual + "] (" + (actual != null ? actual.getClass().getSimpleName() : "null") + ")\n");
 
             }
         }
@@ -146,22 +146,64 @@ public void assertReceivedOnNext(List<T> items) {
      */
     public void assertTerminalEvent() {
         if (onErrorEvents.size() > 1) {
-            throw new AssertionError("Too many onError events: " + onErrorEvents.size());
+            assertionError("Too many onError events: " + onErrorEvents.size());
         }
 
         if (onCompletedEvents.size() > 1) {
-            throw new AssertionError("Too many onCompleted events: " + onCompletedEvents.size());
+            assertionError("Too many onCompleted events: " + onCompletedEvents.size());
         }
 
         if (onCompletedEvents.size() == 1 && onErrorEvents.size() == 1) {
-            throw new AssertionError("Received both an onError and onCompleted. Should be one or the other.");
+            assertionError("Received both an onError and onCompleted. Should be one or the other.");
         }
 
         if (onCompletedEvents.size() == 0 && onErrorEvents.size() == 0) {
-            throw new AssertionError("No terminal events received.");
+            assertionError("No terminal events received.");
         }
     }
 
+    /**
+     * Combines an assertion error message with the current completion and error state of this
+     * TestSubscriber, giving more information when some assertXXX check fails.
+     * @param message the message to use for the error
+     */
+    final void assertionError(String message) {
+        StringBuilder b = new StringBuilder(message.length() + 32);
+
+        b.append(message);
+
+
+        b.append(" (");
+        int c = onCompletedEvents.size();
+        b.append(c);
+        b.append(" completion");
+        if (c != 1) {
+            b.append("s");
+        }
+        b.append(")");
+
+        if (!onErrorEvents.isEmpty()) {
+            int size = onErrorEvents.size();
+            b.append(" (+")
+            .append(size)
+            .append(" error");
+            if (size != 1) {
+                b.append("s");
+            }
+            b.append(")");
+        }
+
+        AssertionError ae = new AssertionError(b.toString());
+        if (!onErrorEvents.isEmpty()) {
+            if (onErrorEvents.size() == 1) {
+                ae.initCause(onErrorEvents.get(0));
+            } else {
+                ae.initCause(new CompositeException(onErrorEvents));
+            }
+        }
+        throw ae;
+    }
+
     // do nothing ... including swallowing errors
     private static Observer<Object> INERT = new Observer<Object>() {
 

src/main/java/rx/observers/TestSubscriber.java

@@ -292,7 +292,7 @@ public void assertTerminalEvent() {
      */
     public void assertUnsubscribed() {
         if (!isUnsubscribed()) {
-            throw new AssertionError("Not unsubscribed.");
+            testObserver.assertionError("Not unsubscribed.");
         }
     }
 
@@ -393,10 +393,10 @@ public Thread getLastSeenThread() {
     public void assertCompleted() {
         int s = testObserver.getOnCompletedEvents().size();
         if (s == 0) {
-            throw new AssertionError("Not completed!");
+            testObserver.assertionError("Not completed!");
         } else
         if (s > 1) {
-            throw new AssertionError("Completed multiple times: " + s);
+            testObserver.assertionError("Completed multiple times: " + s);
         }
     }
 
@@ -409,10 +409,10 @@ public void assertCompleted() {
     public void assertNotCompleted() {
         int s = testObserver.getOnCompletedEvents().size();
         if (s == 1) {
-            throw new AssertionError("Completed!");
+            testObserver.assertionError("Completed!");
         } else
         if (s > 1) {
-            throw new AssertionError("Completed multiple times: " + s);
+            testObserver.assertionError("Completed multiple times: " + s);
         }
     }
 
@@ -427,7 +427,7 @@ public void assertNotCompleted() {
     public void assertError(Class<? extends Throwable> clazz) {
         List<Throwable> err = testObserver.getOnErrorEvents();
         if (err.size() == 0) {
-            throw new AssertionError("No errors");
+            testObserver.assertionError("No errors");
         } else
         if (err.size() > 1) {
             AssertionError ae = new AssertionError("Multiple errors: " + err.size());
@@ -452,7 +452,7 @@ public void assertError(Class<? extends Throwable> clazz) {
     public void assertError(Throwable throwable) {
         List<Throwable> err = testObserver.getOnErrorEvents();
         if (err.size() == 0) {
-            throw new AssertionError("No errors");
+            testObserver.assertionError("No errors");
         } else
         if (err.size() > 1) {
             AssertionError ae = new AssertionError("Multiple errors: " + err.size());
@@ -477,7 +477,7 @@ public void assertNoTerminalEvent() {
         int s = testObserver.getOnCompletedEvents().size();
         if (err.size() > 0 || s > 0) {
             if (err.isEmpty()) {
-                throw new AssertionError("Found " + err.size() + " errors and " + s + " completion events instead of none");
+                testObserver.assertionError("Found " + err.size() + " errors and " + s + " completion events instead of none");
             } else
             if (err.size() == 1) {
                 AssertionError ae = new AssertionError("Found " + err.size() + " errors and " + s + " completion events instead of none");
@@ -500,7 +500,7 @@ public void assertNoTerminalEvent() {
     public void assertNoValues() {
         int s = testObserver.getOnNextEvents().size();
         if (s > 0) {
-            throw new AssertionError("No onNext events expected yet some received: " + s);
+            testObserver.assertionError("No onNext events expected yet some received: " + s);
         }
     }
 
@@ -514,7 +514,7 @@ public void assertNoValues() {
     public void assertValueCount(int count) {
         int s = testObserver.getOnNextEvents().size();
         if (s != count) {
-            throw new AssertionError("Number of onNext events differ; expected: " + count + ", actual: " + s);
+            testObserver.assertionError("Number of onNext events differ; expected: " + count + ", actual: " + s);
         }
     }
 

src/test/java/rx/observers/TestSubscriberTest.java

@@ -18,16 +18,18 @@
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 
-import java.util.Arrays;
+import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.junit.*;
 import org.junit.rules.ExpectedException;
 import org.mockito.InOrder;
 
-import rx.*;
+import rx.Observable;
+import rx.Observer;
 import rx.Scheduler.Worker;
+import rx.Subscriber;
 import rx.exceptions.*;
 import rx.functions.Action0;
 import rx.schedulers.Schedulers;
@@ -610,9 +612,105 @@ public void assertValuesShouldThrowIfNumberOfItemsDoesNotMatch() {
         } catch (AssertionError expected) {
             assertEquals("Number of items does not match. Provided: 2  Actual: 3.\n" +
                     "Provided values: [1, 2]\n" +
-                    "Actual values: [a, b, c]",
+                    "Actual values: [a, b, c]\n (0 completions)",
                     expected.getMessage()
             );
         }
     }
+
+    @Test
+    public void assertionFailureGivesActiveDetails() {
+        TestSubscriber<String> ts = new TestSubscriber<String>();
+
+        ts.onNext("a");
+        ts.onNext("b");
+        ts.onNext("c");
+        ts.onError(new TestException("forced failure"));
+
+        try {
+            ts.assertValues("1", "2");
+            fail();
+        } catch (AssertionError expected) {
+            assertEquals("Number of items does not match. Provided: 2  Actual: 3.\n" +
+                    "Provided values: [1, 2]\n" +
+                    "Actual values: [a, b, c]\n (0 completions) (+1 error)",
+                    expected.getMessage()
+            );
+            Throwable ex = expected.getCause();
+            assertEquals(TestException.class, ex.getClass());
+            assertEquals("forced failure", ex.getMessage());
+        }
+    }
+
+    @Test
+    public void assertionFailureShowsMultipleErrors() {
+        TestSubscriber<String> ts = new TestSubscriber<String>();
+
+        ts.onNext("a");
+        ts.onNext("b");
+        ts.onNext("c");
+        ts.onError(new TestException("forced failure"));
+        ts.onError(new TestException("forced failure 2"));
+
+        try {
+            ts.assertValues("1", "2");
+            fail();
+        } catch (AssertionError expected) {
+            assertEquals("Number of items does not match. Provided: 2  Actual: 3.\n" +
+                    "Provided values: [1, 2]\n" +
+                    "Actual values: [a, b, c]\n (0 completions) (+2 errors)",
+                    expected.getMessage()
+            );
+            Throwable ex = expected.getCause();
+            assertEquals(CompositeException.class, ex.getClass());
+            List<Throwable> list = ((CompositeException)ex).getExceptions();
+            assertEquals(2, list.size());
+            assertEquals("forced failure", list.get(0).getMessage());
+            assertEquals("forced failure 2", list.get(1).getMessage());
+        }
+    }
+
+    @Test
+    public void assertionFailureShowsCompletion() {
+        TestSubscriber<String> ts = new TestSubscriber<String>();
+
+        ts.onNext("a");
+        ts.onNext("b");
+        ts.onNext("c");
+        ts.onCompleted();
+
+        try {
+            ts.assertValues("1", "2");
+            fail();
+        } catch (AssertionError expected) {
+            assertEquals("Number of items does not match. Provided: 2  Actual: 3.\n" +
+                    "Provided values: [1, 2]\n" +
+                    "Actual values: [a, b, c]\n (1 completion)",
+                    expected.getMessage()
+            );
+        }
+    }
+
+    @Test
+    public void assertionFailureShowsMultipleCompletions() {
+        TestSubscriber<String> ts = new TestSubscriber<String>();
+
+        ts.onNext("a");
+        ts.onNext("b");
+        ts.onNext("c");
+        ts.onCompleted();
+        ts.onCompleted();
+
+        try {
+            ts.assertValues("1", "2");
+            fail();
+        } catch (AssertionError expected) {
+            assertEquals("Number of items does not match. Provided: 2  Actual: 3.\n" +
+                    "Provided values: [1, 2]\n" +
+                    "Actual values: [a, b, c]\n (2 completions)",
+                    expected.getMessage()
+            );
+        }
+    }
+
 }