diff --git a/tools/ts-api-guardian/lib/serializer.ts b/tools/ts-api-guardian/lib/serializer.ts
index f575a96373..9bef9a662d 100644
--- a/tools/ts-api-guardian/lib/serializer.ts
+++ b/tools/ts-api-guardian/lib/serializer.ts
@@ -112,7 +112,7 @@ class ResolvedDeclarationEmitter {
   emit(): string {
     const sourceFile = this.program.getSourceFiles().find(sf => sf.fileName === this.fileName);
     if (!sourceFile) {
-      throw new Error(`Source file "${this.fileName}" not found`);
+      throw new Error(`Source file "${this.fileName}" not found                  `);
     }
 
     let output: string[] = [];
@@ -441,4 +441,4 @@ function applyDefaultTagOptions(tagOptions: JsDocTagOptions | undefined): JsDocT
 
 function getName(node: any) {
   return '`' + (node.name && node.name.text ? node.name.text : node.getText()) + '`';
-}
\ No newline at end of file
+}