From be6e02e5fae996d5a673f8047716e006c9869f0c Mon Sep 17 00:00:00 2001
From: Brian Pandola <bpandola@gmail.com>
Date: Wed, 27 Jul 2022 00:19:47 -0700
Subject: [PATCH] Add `key-name` filter for `ec2:DescribeInstances` (#5338)

---
 moto/ec2/utils.py                |  1 +
 tests/test_ec2/test_instances.py | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/moto/ec2/utils.py b/moto/ec2/utils.py
index 08ddcddf2..9511a7cfa 100644
--- a/moto/ec2/utils.py
+++ b/moto/ec2/utils.py
@@ -413,6 +413,7 @@ filter_dict_attribute_mapping = {
     "owner-id": "owner_id",
     "subnet-id": "subnet_id",
     "dns-name": "public_dns",
+    "key-name": "key_name",
 }
 
 
diff --git a/tests/test_ec2/test_instances.py b/tests/test_ec2/test_instances.py
index 750f91f73..0ec008aac 100644
--- a/tests/test_ec2/test_instances.py
+++ b/tests/test_ec2/test_instances.py
@@ -1565,6 +1565,25 @@ def test_run_instance_with_keypair():
     instance.key_name.should.equal("keypair_name")
 
 
+@mock_ec2
+def test_describe_instances_with_keypair_filter():
+    ec2 = boto3.resource("ec2", region_name="us-east-1")
+    for i in range(3):
+        key_name = "kp-single" if i % 2 else "kp-multiple"
+        ec2.create_instances(
+            ImageId=EXAMPLE_AMI_ID, MinCount=1, MaxCount=1, KeyName=key_name
+        )
+    test_data = [
+        (["kp-single"], 1),
+        (["kp-multiple"], 2),
+        (["kp-single", "kp-multiple"], 3),
+    ]
+    for filter_values, expected_instance_count in test_data:
+        _filter = [{"Name": "key-name", "Values": filter_values}]
+        instances_found = list(ec2.instances.filter(Filters=_filter))
+        instances_found.should.have.length_of(expected_instance_count)
+
+
 @mock_ec2
 @mock.patch(
     "moto.ec2.models.instances.settings.ENABLE_KEYPAIR_VALIDATION",