Port test suite from nose to pytest.

This just eliminates all errors on the tests collection. Elimination of
failures is left to the next commit.

tests/test_core/test_auth.py

@@ -4,9 +4,7 @@ import boto3
 import sure  # noqa
 from botocore.exceptions import ClientError
 
-# Ensure 'assert_raises' context manager support for Python 2.6
-import tests.backport_assert_raises
-from nose.tools import assert_raises
+import pytest
 
 from moto import mock_iam, mock_ec2, mock_s3, mock_sts, mock_elbv2, mock_rds2
 from moto.core import set_initial_no_auth_action_count
@@ -179,7 +177,7 @@ def test_invalid_client_token_id():
         aws_access_key_id="invalid",
         aws_secret_access_key="invalid",
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.get_user()
     ex.exception.response["Error"]["Code"].should.equal("InvalidClientTokenId")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -197,7 +195,7 @@ def test_auth_failure():
         aws_access_key_id="invalid",
         aws_secret_access_key="invalid",
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.describe_instances()
     ex.exception.response["Error"]["Code"].should.equal("AuthFailure")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(401)
@@ -216,7 +214,7 @@ def test_signature_does_not_match():
         aws_access_key_id=access_key["AccessKeyId"],
         aws_secret_access_key="invalid",
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.get_user()
     ex.exception.response["Error"]["Code"].should.equal("SignatureDoesNotMatch")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -235,7 +233,7 @@ def test_auth_failure_with_valid_access_key_id():
         aws_access_key_id=access_key["AccessKeyId"],
         aws_secret_access_key="invalid",
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.describe_instances()
     ex.exception.response["Error"]["Code"].should.equal("AuthFailure")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(401)
@@ -255,7 +253,7 @@ def test_access_denied_with_no_policy():
         aws_access_key_id=access_key["AccessKeyId"],
         aws_secret_access_key=access_key["SecretAccessKey"],
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.describe_instances()
     ex.exception.response["Error"]["Code"].should.equal("AccessDenied")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -321,7 +319,7 @@ def test_access_denied_for_run_instances():
         aws_access_key_id=access_key["AccessKeyId"],
         aws_secret_access_key=access_key["SecretAccessKey"],
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.run_instances(MaxCount=1, MinCount=1)
     ex.exception.response["Error"]["Code"].should.equal("AccessDenied")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -352,7 +350,7 @@ def test_access_denied_with_denying_policy():
         aws_access_key_id=access_key["AccessKeyId"],
         aws_secret_access_key=access_key["SecretAccessKey"],
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.create_vpc(CidrBlock="10.0.0.0/16")
     ex.exception.response["Error"]["Code"].should.equal("AccessDenied")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -452,7 +450,7 @@ def test_s3_access_denied_with_denying_attached_group_policy():
         aws_access_key_id=access_key["AccessKeyId"],
         aws_secret_access_key=access_key["SecretAccessKey"],
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.list_buckets()
     ex.exception.response["Error"]["Code"].should.equal("AccessDenied")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -486,7 +484,7 @@ def test_s3_access_denied_with_denying_inline_group_policy():
         aws_secret_access_key=access_key["SecretAccessKey"],
     )
     client.create_bucket(Bucket=bucket_name)
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.get_object(Bucket=bucket_name, Key="sdfsdf")
     ex.exception.response["Error"]["Code"].should.equal("AccessDenied")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -532,7 +530,7 @@ def test_access_denied_with_many_irrelevant_policies():
         aws_access_key_id=access_key["AccessKeyId"],
         aws_secret_access_key=access_key["SecretAccessKey"],
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.create_key_pair(KeyName="TestKey")
     ex.exception.response["Error"]["Code"].should.equal("AccessDenied")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -631,7 +629,7 @@ def test_access_denied_with_temporary_credentials():
         aws_secret_access_key=credentials["SecretAccessKey"],
         aws_session_token=credentials["SessionToken"],
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.create_db_instance(
             DBInstanceIdentifier="test-db-instance",
             DBInstanceClass="db.t3",
@@ -678,7 +676,7 @@ def test_s3_invalid_access_key_id():
         aws_access_key_id="invalid",
         aws_secret_access_key="invalid",
     )
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.list_buckets()
     ex.exception.response["Error"]["Code"].should.equal("InvalidAccessKeyId")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -700,7 +698,7 @@ def test_s3_signature_does_not_match():
         aws_secret_access_key="invalid",
     )
     client.create_bucket(Bucket=bucket_name)
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.put_object(Bucket=bucket_name, Key="abc")
     ex.exception.response["Error"]["Code"].should.equal("SignatureDoesNotMatch")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -736,7 +734,7 @@ def test_s3_access_denied_not_action():
         aws_secret_access_key=access_key["SecretAccessKey"],
     )
     client.create_bucket(Bucket=bucket_name)
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.delete_object(Bucket=bucket_name, Key="sdfsdf")
     ex.exception.response["Error"]["Code"].should.equal("AccessDenied")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(403)
@@ -776,7 +774,7 @@ def test_s3_invalid_token_with_temporary_credentials():
         aws_session_token="invalid",
     )
     client.create_bucket(Bucket=bucket_name)
-    with assert_raises(ClientError) as ex:
+    with pytest.raises(ClientError) as ex:
         client.list_bucket_metrics_configurations(Bucket=bucket_name)
     ex.exception.response["Error"]["Code"].should.equal("InvalidToken")
     ex.exception.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(400)