Merge pull request #48 from artem-zinnatullin/queryobservable-add-query-to-exception

Add Query to the cause of exception in QueryObservable

Author: JakeWharton

sqlbrite/src/androidTest/java/com/squareup/sqlbrite/QueryObservableTest.java

@@ -0,0 +1,64 @@
+package com.squareup.sqlbrite;
+
+import android.database.Cursor;
+import android.database.MatrixCursor;
+import android.support.test.runner.AndroidJUnit4;
+
+import com.squareup.sqlbrite.SqlBrite.Query;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import rx.Observable;
+import rx.functions.Func1;
+import rx.observers.TestSubscriber;
+
+import static com.google.common.truth.Truth.assertThat;
+
+@RunWith(AndroidJUnit4.class)
+public final class QueryObservableTest {
+
+  @Test public void mapToListThrowsFromQueryRun() {
+    TestSubscriber<Object> testSubscriber = new TestSubscriber<>();
+
+    new QueryObservable(Observable.<Query>just(new Query() {
+      @Override public Cursor run() {
+        throw new IllegalStateException("test exception");
+      }
+    })).mapToList(new Func1<Cursor, Object>() {
+      @Override public Object call(Cursor cursor) {
+        throw new AssertionError("Must not be called");
+      }
+    }).subscribe(testSubscriber);
+
+    testSubscriber.awaitTerminalEvent();
+    testSubscriber.assertNoValues();
+    assertThat(testSubscriber.getOnErrorEvents()).hasSize(1);
+
+    IllegalStateException expected = (IllegalStateException) testSubscriber.getOnErrorEvents().get(0);
+    assertThat(expected).hasMessage("test exception");
+  }
+
+  @Test public void mapToListThrowsFromMapFunction() {
+    TestSubscriber<Object> testSubscriber = new TestSubscriber<>();
+
+    new QueryObservable(Observable.<Query>just(new Query() {
+      @Override public Cursor run() {
+        MatrixCursor cursor = new MatrixCursor(new String[]{"col1"});
+        cursor.addRow(new Object[]{"value1"});
+        return cursor;
+      }
+    })).mapToList(new Func1<Cursor, Object>() {
+      @Override public Object call(Cursor cursor) {
+        throw new IllegalStateException("test exception");
+      }
+    }).subscribe(testSubscriber);
+
+    testSubscriber.awaitTerminalEvent();
+    testSubscriber.assertNoValues();
+    assertThat(testSubscriber.getOnErrorEvents()).hasSize(1);
+
+    IllegalStateException expected = (IllegalStateException) testSubscriber.getOnErrorEvents().get(0);
+    assertThat(expected).hasMessage("test exception");
+  }
+}

sqlbrite/src/main/java/com/squareup/sqlbrite/QueryObservable.java

@@ -8,6 +8,8 @@
 import java.util.List;
 import rx.Observable;
 import rx.Subscriber;
+import rx.exceptions.Exceptions;
+import rx.exceptions.OnErrorThrowable;
 import rx.functions.Func1;
 
 /** An {@link Observable} of {@link Query} which offers query-specific convenience operators. */
@@ -41,17 +43,22 @@ public final <T> Observable<List<T>> mapToList(@NonNull final Func1<Cursor, T> m
       public Subscriber<? super Query> call(final Subscriber<? super List<T>> subscriber) {
         return new Subscriber<Query>(subscriber) {
           @Override public void onNext(Query query) {
-            Cursor cursor = query.run();
-            List<T> items = new ArrayList<>(cursor.getCount());
             try {
-              while (cursor.moveToNext() && !subscriber.isUnsubscribed()) {
-                items.add(mapper.call(cursor));
+              Cursor cursor = query.run();
+              List<T> items = new ArrayList<>(cursor.getCount());
+              try {
+                while (cursor.moveToNext() && !subscriber.isUnsubscribed()) {
+                  items.add(mapper.call(cursor));
+                }
+              } finally {
+                cursor.close();
               }
-            } finally {
-              cursor.close();
-            }
-            if (!subscriber.isUnsubscribed()) {
-              subscriber.onNext(items);
+              if (!subscriber.isUnsubscribed()) {
+                subscriber.onNext(items);
+              }
+            } catch (Throwable e) {
+              Exceptions.throwIfFatal(e);
+              onError(OnErrorThrowable.addValueAsLastCause(e, query));
             }
           }