From e31ea464ac678e6f5c2d0197ae29e68d0c04e7a7 Mon Sep 17 00:00:00 2001
From: Matthew Bonig <matthew.bonig@gmail.com>
Date: Thu, 27 Feb 2020 14:55:59 -0700
Subject: [PATCH] adding additional tests

---
 packages/@aws-cdk/aws-iam/lib/policy-statement.ts |  3 +++
 .../aws-iam/test/policy-statement.test.ts         | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/packages/@aws-cdk/aws-iam/lib/policy-statement.ts b/packages/@aws-cdk/aws-iam/lib/policy-statement.ts
index 3d47948998bbc..83c223ddbd957 100644
--- a/packages/@aws-cdk/aws-iam/lib/policy-statement.ts
+++ b/packages/@aws-cdk/aws-iam/lib/policy-statement.ts
@@ -20,6 +20,9 @@ export class PolicyStatement {
       if (typeof (field) !== "string" && !Array.isArray(field)) {
         throw new Error("Fields must be either a string or an array of strings");
       }
+      if (Array.isArray(field) && !field.reduce((acc: boolean, f: any) => (acc && typeof (f) === "string"), true)) {
+        throw new Error("Fields must be either a string or an array of strings");
+      }
       return Array.isArray(field) ? field : [field];
     };
 
diff --git a/packages/@aws-cdk/aws-iam/test/policy-statement.test.ts b/packages/@aws-cdk/aws-iam/test/policy-statement.test.ts
index 34035cda07290..8496a865f228f 100644
--- a/packages/@aws-cdk/aws-iam/test/policy-statement.test.ts
+++ b/packages/@aws-cdk/aws-iam/test/policy-statement.test.ts
@@ -237,6 +237,21 @@ describe('IAM policy statement', () => {
       expect(stack.resolve(doc)).toEqual(policyDocument);
     });
 
+    test('throws error with field data being object', () => {
+      expect(() => {
+        PolicyStatement.fromJson({
+          Action: {}
+        });
+      }).toThrow(/Fields must be either a string or an array of strings/);
+    });
+
+    test('throws error with field data being object', () => {
+      expect(() => {
+        PolicyStatement.fromJson({
+          Action: [{}]
+        });
+      }).toThrow(/Fields must be either a string or an array of strings/);
+    });
   });
 
 });