From d98152a3d8c72e4f5ac4c6fa10a615b12090c8f7 Mon Sep 17 00:00:00 2001
From: Anix <anik220798@gmail.com>
Date: Wed, 17 Jun 2020 14:10:41 +0530
Subject: [PATCH] Update: added empty error array check for false negative
 (#13200)

* Update: added empty error array check for false negative

* Chore: message refactore

* Chore: fixed tests

* Update: throw error for errors: 0 in test files

* Update: changed error message

* Chore: changed assertion message
---
 lib/rule-tester/rule-tester.js       |  9 ++++++++
 tests/lib/rule-tester/rule-tester.js | 34 +++++++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/lib/rule-tester/rule-tester.js b/lib/rule-tester/rule-tester.js
index 77df1def893..3e391576716 100644
--- a/lib/rule-tester/rule-tester.js
+++ b/lib/rule-tester/rule-tester.js
@@ -644,6 +644,10 @@ class RuleTester {
             assert.ok(item.errors || item.errors === 0,
                 `Did not specify errors for an invalid test of ${ruleName}`);
 
+            if (Array.isArray(item.errors) && item.errors.length === 0) {
+                assert.fail("Invalid cases must have at least one error");
+            }
+
             const ruleHasMetaMessages = hasOwnProperty(rule, "meta") && hasOwnProperty(rule.meta, "messages");
             const friendlyIDList = ruleHasMetaMessages ? `[${Object.keys(rule.meta.messages).map(key => `'${key}'`).join(", ")}]` : null;
 
@@ -651,6 +655,11 @@ class RuleTester {
             const messages = result.messages;
 
             if (typeof item.errors === "number") {
+
+                if (item.errors === 0) {
+                    assert.fail("Invalid cases must have 'error' value greater than 0");
+                }
+
                 assert.strictEqual(messages.length, item.errors, util.format("Should have %d error%s but had %d: %s",
                     item.errors, item.errors === 1 ? "" : "s", messages.length, util.inspect(messages)));
             } else {
diff --git a/tests/lib/rule-tester/rule-tester.js b/tests/lib/rule-tester/rule-tester.js
index fedc237d64c..7e26e1a826c 100644
--- a/tests/lib/rule-tester/rule-tester.js
+++ b/tests/lib/rule-tester/rule-tester.js
@@ -463,6 +463,37 @@ describe("RuleTester", () => {
         }, expectedErrorMessage);
     });
 
+    it("should throw error for empty error array", () => {
+        assert.throws(() => {
+            ruleTester.run("suggestions-messageIds", require("../../fixtures/testers/rule-tester/suggestions").withMessageIds, {
+                valid: [],
+                invalid: [{
+                    code: "var foo;",
+                    errors: []
+                }]
+            });
+        }, /Invalid cases must have at least one error/u);
+    });
+
+    it("should throw error for errors : 0", () => {
+        assert.throws(() => {
+            ruleTester.run(
+                "suggestions-messageIds",
+                require("../../fixtures/testers/rule-tester/suggestions")
+                    .withMessageIds,
+                {
+                    valid: [],
+                    invalid: [
+                        {
+                            code: "var foo;",
+                            errors: 0
+                        }
+                    ]
+                }
+            );
+        }, /Invalid cases must have 'error' value greater than 0/u);
+    });
+
     it("should not skip column assertion if column is a falsy value", () => {
         assert.throws(() => {
             ruleTester.run("no-eval", require("../../fixtures/testers/rule-tester/no-eval"), {
@@ -732,7 +763,7 @@ describe("RuleTester", () => {
                 {
                     code: "eval(foo)",
                     parser: require.resolve("esprima"),
-                    errors: [{}]
+                    errors: [{ line: 1 }]
                 }
             ]
         });
@@ -1893,4 +1924,5 @@ describe("RuleTester", () => {
         });
 
     });
+
 });