Improve implementation coverage (and layout)

tests/test_ec2instanceconnect/test_ec2instanceconnect_boto3.py

@@ -0,0 +1,23 @@
+import boto3
+
+from moto import mock_ec2instanceconnect
+
+pubkey = """ssh-rsa
+AAAAB3NzaC1yc2EAAAADAQABAAABAQDV5+voluw2zmzqpqCAqtsyoP01TQ8Ydx1eS1yD6wUsHcPqMIqpo57YxiC8XPwrdeKQ6GG6MC3bHsgXoPypGP0LyixbiuLTU31DnnqorcHt4bWs6rQa7dK2pCCflz2fhYRt5ZjqSNsAKivIbqkH66JozN0SySIka3kEV79GdB0BicioKeEJlCwM9vvxafyzjWf/z8E0lh4ni3vkLpIVJ0t5l+Qd9QMJrT6Is0SCQPVagTYZoi8+fWDoGsBa8vyRwDjEzBl28ZplKh9tSyDkRIYszWTpmK8qHiqjLYZBfAxXjGJbEYL1iig4ZxvbYzKEiKSBi1ZMW9iWjHfZDZuxXAmB
+example
+"""
+
+
+@mock_ec2instanceconnect
+def test_send_ssh_public_key():
+    client = boto3.client("ec2-instance-connect", region_name="us-east-1")
+    fake_request_id = "example-2a47-4c91-9700-e37e85162cb6"
+
+    response = client.send_ssh_public_key(
+        InstanceId="i-abcdefg12345",
+        InstanceOSUser="ec2-user",
+        SSHPublicKey=pubkey,
+        AvailabilityZone="us-east-1a",
+    )
+
+    assert response["RequestId"] == fake_request_id