Add ec2 filtering by instance state

tests/test_ec2/test_instances.py

@@ -2,6 +2,7 @@ import base64
 
 import boto
 from boto.ec2.instance import Reservation, InstanceAttribute
+from boto.exception import EC2ResponseError
 import sure  # flake8: noqa
 
 from moto import mock_ec2
@@ -69,6 +70,34 @@ def test_get_instances_by_id():
     instance_ids = [instance.id for instance in reservation.instances]
     instance_ids.should.equal([instance1.id, instance2.id])
 
+    # Call get_all_instances with a bad id should raise an error
+    conn.get_all_instances.when.called_with(instance_ids=[instance1.id, "i-1234abcd"]).should.throw(
+        EC2ResponseError,
+        "The instance ID 'i-1234abcd' does not exist"
+    )
+
+
+@mock_ec2
+def test_get_instances_filtering_by_state():
+    conn = boto.connect_ec2()
+    reservation = conn.run_instances('ami-1234abcd', min_count=3)
+    instance1, instance2, instance3 = reservation.instances
+
+    conn.terminate_instances([instance1.id])
+
+    reservations = conn.get_all_instances(filters={'instance-state-name': 'pending'})
+    reservations.should.have.length_of(1)
+    # Since we terminated instance1, only instance2 and instance3 should be returned
+    instance_ids = [instance.id for instance in reservations[0].instances]
+    set(instance_ids).should.equal(set([instance2.id, instance3.id]))
+
+    reservations = conn.get_all_instances([instance2.id], filters={'instance-state-name': 'pending'})
+    reservations.should.have.length_of(1)
+    instance_ids = [instance.id for instance in reservations[0].instances]
+    instance_ids.should.equal([instance2.id])
+
+    conn.get_all_instances.when.called_with(filters={'not-implemented-filter': 'foobar'}).should.throw(NotImplementedError)
+
 
 @mock_ec2
 def test_instance_start_and_stop():