Merge pull request #1524 from ckeditor/t/1474

Other: Added new OT tests, reached 100% code coverage, fixed multiple OT scenarios, removed unreachable code. Closes #1474.

src/model/operation/mergeoperation.js

@@ -130,14 +130,14 @@ export default class MergeOperation extends Operation {
 		const targetElement = this.targetPosition.parent;
 
 		// Validate whether merge operation has correct parameters.
-		if ( !sourceElement || !sourceElement.is( 'element' ) ) {
+		if ( !sourceElement || !sourceElement.is( 'element' ) || !sourceElement.parent ) {
 			/**
 			 * Merge source position is invalid.
 			 *
 			 * @error merge-operation-source-position-invalid
 			 */
 			throw new CKEditorError( 'merge-operation-source-position-invalid: Merge source position is invalid.' );
-		} else if ( !targetElement || !targetElement.is( 'element' ) ) {
+		} else if ( !targetElement || !targetElement.is( 'element' ) || !targetElement.parent ) {
 			/**
 			 * Merge target position is invalid.
 			 *

src/model/operation/splitoperation.js

@@ -155,13 +155,27 @@ export default class SplitOperation extends Operation {
 			 * @error split-operation-position-invalid
 			 */
 			throw new CKEditorError( 'split-operation-position-invalid: Split position is invalid.' );
+		} else if ( !element.parent ) {
+			/**
+			 * Cannot split root element.
+			 *
+			 * @error split-operation-split-in-root
+			 */
+			throw new CKEditorError( 'split-operation-split-in-root: Cannot split root element.' );
 		} else if ( this.howMany != element.maxOffset - this.position.offset ) {
 			/**
 			 * Split operation specifies wrong number of nodes to move.
 			 *
 			 * @error split-operation-how-many-invalid
 			 */
 			throw new CKEditorError( 'split-operation-how-many-invalid: Split operation specifies wrong number of nodes to move.' );
+		} else if ( this.graveyardPosition && !this.graveyardPosition.nodeAfter ) {
+			/**
+			 * Graveyard position invalid.
+			 *
+			 * @error split-operation-graveyard-position-invalid
+			 */
+			throw new CKEditorError( 'split-operation-graveyard-position-invalid: Graveyard position invalid.' );
 		}
 	}