Allow calling first() and single() multiple times as long as we're not passed the first record

Author: boggle

driver/src/main/java/org/neo4j/driver/internal/InternalResultCursor.java

@@ -173,7 +173,7 @@ else if ( records == 0) {
     @Override
     public Record first()
     {
-        if( position() > 0 )
+        if( position() >= 1 )
         {
             throw new NoSuchRecordException( "Cannot retrieve the first record, because this result cursor has been moved already. " +
                                              "Please ensure you are not calling `first` multiple times, or are mixing it with calls " +

driver/src/main/java/org/neo4j/driver/v1/ResultCursor.java

@@ -92,7 +92,7 @@ public interface ResultCursor extends RecordAccessor, Resource
 
     /**
      * Return the first record in the stream. Fail with an exception if the stream is empty
-     * or if this cursor has already been used to move "into" the stream.
+     * or if this cursor has already been used to move past the first record.
      *
      * @return the first record in the stream
      * @throws NoSuchRecordException if there is no first record or the cursor has been used already
@@ -102,7 +102,7 @@ public interface ResultCursor extends RecordAccessor, Resource
 
     /**
      * Return a field value from the first record in the stream. Fail with an exception if the stream is empty
-     * or if this cursor has already been used to move "into" the stream.
+     * or if this cursor has already been used to move past the first record.
      *
      * @param fieldName the name of the field to return from the first record in the stream
      * @return the specified field from the first record in the stream
@@ -113,7 +113,7 @@ public interface ResultCursor extends RecordAccessor, Resource
 
     /**
      * Return a field value from the first record in the stream. Fail with an exception if the stream is empty
-     * or if this cursor has already been used to move "into" the stream.
+     * or if this cursor has already been used to move past the first record.
      *
      * @param index the index of the field to return from the first record in the stream
      * @return the specified field from the first record in the stream
@@ -124,7 +124,7 @@ public interface ResultCursor extends RecordAccessor, Resource
 
     /**
      * Move to the first record and return an immutable copy of it, failing if there is not exactly
-     * one record in the stream, or if this cursor has already been used to move "into" the stream.
+     * one record in the stream, or if this cursor has already been used to move past the first record.
      *
      * @return the first and only record in the stream
      * @throws NoSuchRecordException if there is not exactly one record in the stream, or if the cursor has been used already
@@ -133,7 +133,7 @@ public interface ResultCursor extends RecordAccessor, Resource
 
     /**
      * Move to the first record and return a field value from it, failing if there is not exactly
-     * one record in the stream, or if this cursor has already been used to move "into" the stream.
+     * one record in the stream, or if this cursor has already been used to move past the first record.
      *
      * @param fieldName the name of the field to return from the first and only record in the stream
      * @return the value of the specified field of the first and only record in the stream
@@ -143,7 +143,7 @@ public interface ResultCursor extends RecordAccessor, Resource
 
     /**
      * Move to the first record and return a field value from it, failing if there is not exactly
-     * one record in the stream, or if this cursor has already been used to move "into" the stream.
+     * one record in the stream, or if this cursor has already been used to move past the first record.
      *
      * @param index the index of the field to return from the first and only record in the stream
      * @return the value of the specified field of the first and only record in the stream

driver/src/test/java/org/neo4j/driver/internal/InternalResultCursorTest.java

@@ -70,6 +70,22 @@ public void iterationShouldWorksAsExpected()
         assertFalse( result.next() );
     }
 
+    @Test
+    public void firstPastFirstShouldFail()
+    {
+        // GIVEN
+        ResultCursor result = createResult( 3 );
+        result.next();
+        result.next();
+
+
+        // THEN
+        expectedException.expect( NoSuchRecordException.class );
+
+        // THEN
+        result.first();
+    }
+
     @Test
     public void firstOfFieldNameShouldWorkAsExpected()
     {
@@ -92,6 +108,50 @@ public void firstOfFieldIndexShouldWorkAsExpected()
         assertFalse( result.atEnd() );
     }
 
+    @Test
+    public void singlePastFirstShouldFail()
+    {
+        // GIVEN
+        ResultCursor result = createResult( 2 );
+        result.next();
+        result.next();
+
+
+        // THEN
+        expectedException.expect( NoSuchRecordException.class );
+
+        // THEN
+        result.single();
+    }
+
+    @Test
+    public void singleNoneShouldFail()
+    {
+        // GIVEN
+        ResultCursor result = createResult( 0 );
+
+
+        // THEN
+        expectedException.expect( NoSuchRecordException.class );
+
+        // THEN
+        result.single();
+    }
+
+    @Test
+    public void singleWhenMoreThanOneShouldFail()
+    {
+        // GIVEN
+        ResultCursor result = createResult( 2 );
+
+
+        // THEN
+        expectedException.expect( NoSuchRecordException.class );
+
+        // THEN
+        result.single();
+    }
+
     @Test
     public void singleOfFieldNameShouldWorkAsExpected()
     {