From a4f15c2a6de24e678c9c93fcc24e12f539cc6a96 Mon Sep 17 00:00:00 2001
From: Alan Agius <alan.agius4@gmail.com>
Date: Wed, 3 Oct 2018 18:59:24 +0200
Subject: [PATCH] fix(@angular-devkit/build-angular): `ng test` without
 `reporters` no longer print error

Closes #12455
---
 packages/angular_devkit/build_angular/src/karma/index.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/angular_devkit/build_angular/src/karma/index.ts b/packages/angular_devkit/build_angular/src/karma/index.ts
index 3d1b066d9f1b..8e41e89a7dc5 100644
--- a/packages/angular_devkit/build_angular/src/karma/index.ts
+++ b/packages/angular_devkit/build_angular/src/karma/index.ts
@@ -73,9 +73,13 @@ export class KarmaBuilder implements Builder<KarmaBuilderSchema> {
 
         if (options.reporters) {
           // Split along commas to make it more natural, and remove empty strings.
-          karmaOptions.reporters = options.reporters
+          const reporters = options.reporters
             .reduce<string[]>((acc, curr) => acc.concat(curr.split(/,/)), [])
             .filter(x => !!x);
+
+          if (reporters.length > 0) {
+            karmaOptions.reporters = reporters;
+          }
         }
 
         const sourceRoot = builderConfig.sourceRoot && resolve(root, builderConfig.sourceRoot);