Output +/- on diff so added/removed empty lines are visible. (palanti…

…r#3973)

src/test.ts

@@ -250,11 +250,17 @@ function displayDiffResults(diffResults: diff.IDiffResult[], extension: string,
 
     for (const diffResult of diffResults) {
         let color = chalk.grey;
+        let prefix = "  ";
         if (diffResult.added) {
             color = chalk.green.underline;
+            prefix = "+ ";
         } else if (diffResult.removed) {
             color = chalk.red.underline;
+            prefix = "- ";
         }
-        logger.log(color(diffResult.value));
+        logger.log(color(diffResult.value.split(/\r\n|\r|\n/)
+            // strings end on a newline which we do not want to include the prefix.
+            // tslint:disable-next-line:prefer-template
+            .map((line, index, array) => index === array.length - 1 ? line : prefix + line + "\n").join("")));
     }
 }