1 files changed, 47 insertions, 0 deletions
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/rejects-requires-await.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/rejects-requires-await.js
new file mode 100644
index 0000000000..a7e7d9d7e2
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/rejects-requires-await.js
@@ -0,0 +1,47 @@
+/**
+ * @fileoverview Ensure Assert.rejects is preceded by await.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+module.exports = {
+  meta: {
+    docs: {
+      url: "https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/rules/reject-requires-await.html",
+    },
+    messages: {
+      rejectRequiresAwait: "Assert.rejects needs to be preceded by await.",
+    },
+    schema: [],
+    type: "problem",
+  },
+
+  create(context) {
+    return {
+      CallExpression(node) {
+        if (node.callee.type === "MemberExpression") {
+          let memexp = node.callee;
+          if (
+            memexp.object.type === "Identifier" &&
+            memexp.object.name === "Assert" &&
+            memexp.property.type === "Identifier" &&
+            memexp.property.name === "rejects"
+          ) {
+            // We have ourselves an Assert.rejects.
+
+            if (node.parent.type !== "AwaitExpression") {
+              context.report({
+                node,
+                messageId: "rejectRequiresAwait",
+              });
+            }
+          }
+        }
+      },
+    };
+  },
+};